You are an expert CBSE XII CS Computer Science teacher, examiner, and study material creator.

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SCOPE — READ BEFORE GENERATING ANYTHING
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Today's lecture covers ONE topic only: "List and tuple operations"
Lecture number 11 of 91 | Duration: 35 minutes | Board: CBSE
Chapter: Computational Thinking and Programming – 2

HARD RULE: Every piece of content you generate — notes, examples, questions, tips —
must be directly relevant to "List and tuple operations" only.
DO NOT pull content, examples, or questions from any other topic or chapter.

LECTURE MODE: SUBTOPIC PYQ PRACTICE
- Scope: "List and tuple operations" only.
- Do not reteach the topic from scratch. Use a short recap only when a PYQ needs it.
- Main output must be previous-year-question practice: question analysis, marking points, model answers, common mistakes, and timed strategy.
- Use the 40 real PYQ record(s) provided below as the source of truth. Do not fabricate board years, marks, or questions.

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SECTION 1: LECTURE INFORMATION
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Class: XII CS | Subject: Computer Science | Board: CBSE
Topic: List and tuple operations PYQ
Subtopics to cover today:
- List and tuple operations

Student level: Class XII, CBSE Board, average to above-average students preparing for board exams

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SECTION 2: TEACHER'S REFERENCE NOTES
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List and tuple operations PYQ

PYQ PRACTICE SCOPE: List and tuple operations.
Concept ID: U1_LIST_TUPLE_OPS.
Use only previous-year questions whose concept_ids include U1_LIST_TUPLE_OPS.

Teaching ideas: Timed PYQ round, board solution, peer marking, and correction of recurring examiner traps.

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SECTION 3: EXAM FREQUENCY DATA (Year-wise)
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Teaching priority: HIGH
High-yield concepts: List and tuple operations

| Year | Questions | Marks |
|------|-----------|-------|
| 2021 | 7 | 7 |
| 2023 | 8 | 10 |
| 2024 | 12 | 14 |
| 2025 | 9 | 12 |
| 2026 | 4 | 5 |
| **Total** | **40** | **48** |

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SECTION 4: ACTUAL PREVIOUS YEAR QUESTIONS
(Scope: "List and tuple operations" only — 40 questions from board papers)
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PYQ LECTURE RULE: use these questions as the source pool for practice.
- Cover every concept tested across the full PYQ pool.
- Fully discuss the highest-yield 15 and compactly list the rest with concept tested + exam trap.
- Compression and representative questions are allowed only for repeated patterns beyond the fully discussed 15.
- Do not fabricate board years, marks, sections, or questions.
- Representative questions must never be labelled as real board questions.


--- 2021 Board Exam (7 questions | 7 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Consider a declaration L = (1, 'Python', '3.14').
Which of the following represents the data type of L?
a) list
b) tuple
c) dictionary
d) string

Q2. [MCQ] [1M] [Easy] Section-A
Given a Tuple tup1= (10, 20, 30, 40, 50, 60, 70, 80, 90).
What will be the output of print(tup1[3:7:2])?
a) (40,50,60,70,80)
b) (40,50,60,70)
c) [40,60]
d) (40,60)

Q3. [MCQ] [1M] [Easy] Section-A
The return type of the input() function is:
a) string
b) integer
c) list
d) tuple

Q4. [MCQ] [1M] [Easy] Section-A
Consider a tuple tup1 = (10, 15, 25, 30). Identify the statement that will result in an error.
a) print(tup1[2])
b) tup1[2] = 20
c) print(min(tup1))
d) print(len(tup1))

Q5. [MCQ] [1M] [Easy] Section-B
Identify the output of the following Python statements.
x = [[10.0, 11.0, 12.0],[13.0, 14.0, 15.0]]
y = x[1][2]
print(y)
a) 12.0
b) 13.0
c) 14.0
d) 15.0

Q6. [MCQ] [1M] [Easy] Section-B
Identify the output of the following Python statements.
lst1 = [10, 15, 20, 25, 30]
lst1.insert(3, 4)
lst1.insert(2, 3)
print(lst1[-5])
a) 2
b) 3
c) 4
d) 20

Q7. [MCQ] [1M] [Easy] Section-B
What will be the output of the following code?
tup1 = (1,2,[1,2],3)
tup1[2][1]=3.14
print(tup1)
a) (1,2,[3.14,2],3)
b) (1,2,[1,3.14],3)
c) (1,2,[1,2],3.14)
d) Error Message

--- 2023 Board Exam (8 questions | 10 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Given the following Tuple
Tup= (10, 20, 30, 50)
Which of the following statements will result in an error ?
(a) print (Tup[0])
(b) Tup.insert (2,3)
(c) print (Tup[1:2])
(d) print(len(Tup) )

Q2. [MCQ] [1M] [Easy] Section-A
Fill in the blank.
________ function is used to arrange the elements of a list in ascending order.
(a) sort()
(b) arrange ()
(c) ascending()
(d) asort()

Q3. [MCQ] [1M] [Easy] Section-A
Which function returns the sum of all elements of a list ?
(a) count ()
(b) sum()
(c) total()
(d) add()

Q4. [MCQ] [1M] [Easy] Section-A
Fill in the blank :
________ is not a valid built-in function for list manipulations.
(a) count()
(b) length()
(c) append()
(d) extend()

Q5. [MCQ] [1M] [Easy] Section-A
Which of the following statement(s) would give an error during execution of the following code?
tup = (20,30,40,50,80,79)
print(tup)        #Statement 1
print(tup[3]+50)  #Statement 2
print(max(tup))   #Statement 3
tup[4]=80         #Statement 4
a) Statement 1
b) Statement 2
c) Statement 3
d) Statement 4

Q6. [Assertion-Reason] [1M] [Easy] Section-A
Assertion(A): List is an immutable data type.
Reasoning(R): When an attempt is made to update the value of an immutable variable, the old variable is destroyed and a new variable is created by the same name in memory.
a) Both A and R are true and R is the correct explanation for A
b) Both A and R are true and R is not the correct explanation for A
c) A is True but R is False
d) A is false but R is True

Q7. [Output Prediction] [2M] [Easy] Section-B
(a) Given is a Python list declaration :
Listofnames=["Ankit", "Ashish", "Rajan", "Rajat"]
Write the output of :
print (Listofnames [-1:-4:-1])

(b) Consider the following tuple declaration :
tupl=(10,20,30,40)
Write the output of :
print (tupl.index(20))

Q8. [Short Answer] [2M] [Easy] Section-B
Write the Python statement for each of the following tasks using BUILT-IN functions/methods only:
(i) To insert an element 200 at the third position, in the list L1.
(ii) To check whether a string named message ends with a full stop / period or not.

--- 2024 Board Exam (12 questions | 14 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
What will be the output of the following code ?
L=[10,20,30,40,50]
print(L[2:4])
(A) [20,30]
(B) [10,20,30,40]
(C) [30,40]
(D) [30,40,50]

Q2. [MCQ] [1M] [Easy] Section-A
Fill in the blank:
________ is the method of a list which is used to add an element in the end of the existing list.
(A) append()
(B) add()
(C) insert()
(D) extend()

Q3. [Short Answer] [1M] [Easy] Section-A
State True or False :
"In Python, tuple is a mutable data type".

Q4. [MCQ] [1M] [Easy] Section-A
For the following Python statement :
N = (25)
What shall be the type of N ?
(A) Integer
(B) String
(C) Tuple
(D) List

Q5. [MCQ] [1M] [Easy] Section-A
What will be the output of the following code?
tuple1 = (1, 2, 3)
tuple2 = tuple1
tuple1 += (4,)
print(tuple1 == tuple2)
a) True
b) False
c) tuple1
d) Error

Q6. [MCQ] [1M] [Easy] Section-A
What does the list.remove(x) method do in Python?
a) Removes the element at index x from the list
b) Removes the first occurrence of value x from the list
c) Removes all occurrences of value x from the list
d) Removes the last occurrence of value x from the list

Q7. [Short Answer] [1M] [Easy] Section-B
If L1=[1,2,3,2,1,2,4,2, . . . ], and L2=[10,20,30, . . .], answer using built-in functions only.
Write a statement to count the occurrences of 4 in L1.

Q8. [Short Answer] [1M] [Easy] Section-B
If L1=[1,2,3,2,1,2,4,2, . . . ], and L2=[10,20,30, . . .], answer using built-in functions only.
Write a statement to sort the elements of list L1 in ascending order.

Q9. [Short Answer] [1M] [Easy] Section-B
If L1=[1,2,3,2,1,2,4,2, . . . ], and L2=[10,20,30, . . .], answer using built-in functions only.
Write a statement to insert all the elements of L2 at the end of L1.

Q10. [Short Answer] [1M] [Easy] Section-B
If L1=[1,2,3,2,1,2,4,2, . . . ], and L2=[10,20,30, . . .], answer using built-in functions only.
Write a statement to reverse the elements of list L2.

Q11. [Output Prediction] [2M] [Easy] Section-B
Write the output of the following Python code:
List=[10,20,30]
List.extend([40,50])
print(List)
print(List.index(40))
print(List.count(10))

Q12. [Short Answer] [2M] [Easy] Section-B
(a) Write the Python statement for each of the following tasks using BUILT-IN functions/methods only :
(i) To delete an element 10 from the list lst.
(ii) To replace the string "This" with "That" in the string str1.

--- 2025 Board Exam (9 questions | 12 marks) ---

Q1. [Short Answer] [1M] [Easy] Section-A
State True or False:
"A Python List must always contain all its elements of same data type."

Q2. [MCQ] [1M] [Easy] Section-A
Consider the statements given below and then choose the correct output from the given options:
L=['TIC', 'TAC']
print(L[::-1])
(A) ['crT', 'caT']
(B) ['TIc', 'TAC']
(C) ['car', 'CIT']
(D) ['TAC', 'TIC']

Q3. [Short Answer] [1M] [Easy] Section-A
State if following statement is True or False:
If T is a tuple and L is a list, then T+L is a valid statement in Python.

Q4. [Output Prediction] [1M] [Easy] Section-A
What will be the output of the following code segment ?
p=list("Session 2024–25")
print(p[10:20:])

Q5. [MCQ] [1M] [Easy] Section-A
Which of the following list methods accepts exactly 2 parameters ?
(A) append()
(B) extend()
(C) insert()
(D) pop()

Q6. [MCQ] [1M] [Easy] Section-A
What will be the output of the following code?
L = ["India", "Incredible", "Bharat"]
print(L[1][0] + L[2][-1])
a) IT
b) it
c) It
d) iT

Q7. [Assertion-Reason] [1M] [Easy] Section-A
Assertion (A): The expression (1, 2, 3, 4).append(5) in Python will modify the original sequence datatype.
Reason (R): The append() method adds an element to the end of a list and modifies the list in place.
a) Both A and R are True and R is the correct explanation for A.
b) Both A and R are True and R is not the correct explanation for A.
c) A is True but R is False.
d) A is False but R is True.

Q8. [Programming] [2M] [Easy] Section-B
A. (Answer using Python built-in methods/functions only):
I. Write a statement to find the index of the first occurrence of the substring "good" in a string named review.
II. Write a statement to sort the elements of list L1 in descending order.

Q9. [Output Prediction] [3M] [Medium] Section-C
B. Predict the output of the following Python code:
wildlife_sanctuary = ["Kaziranga", "Ranthambhore", "Jim Corbett", "Sundarbans", "Periyar", "Gir", "Bandipur"]
output = [ ]
for sanctuary in wildlife_sanctuary:
    if sanctuary[-1] in 'aeiou':
        output.append(sanctuary[0].upper())
print(output)

--- 2026 Board Exam (4 questions | 5 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
What is the output of the following code snippet ?
s = 'War and Peace by Leo Tolstoy'
print(s.partition("by"))
(A) ('War and Peace ', 'by', ' Leo Tolstoy')
(B) ['War and Peace ', 'by', ' Leo Tolstoy']
(C) ('War and Peace ', ' Leo Tolstoy')
(D) ['War and Peace ', ' Leo Tolstoy']

Q2. [MCQ] [1M] [Easy] Section-A
What will be the output of the following code snippet ?
t = tuple('tuple')
t2 = t[2],
t += t2
print(t)
(A) ('tuple')
(B) ('tuple','p')
(C) ('t', 'u', 'p', 'l', 'e', 'p')
(D) ('t', 'u', 'p', 'l', 'e')

Q3. [Assertion-Reason] [1M] [Easy] Section-A
Assertion (A) : [1,2,3]+'123' is an invalid expression in Python.
Reason (R) : In Python, a list cannot be concatenated with a string.
(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation for Assertion (A).
(B) Both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation for Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.

Q4. [Short Answer] [2M] [Easy] Section-B
Write a Python statement to perform the following tasks : (USE BUILT_IN FUNCTIONS / METHODS ONLY)
(i) To create a new list L1 containing the elements of list L arranged in ascending order, without modifying list L.
(ii) A statement to check whether the given character, ch is an alphabet or a number.

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QUESTION PATTERN BANK (What the board actually asks for THIS topic)
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Scope: ONLY questions for today's lecture topic are listed below.
DO NOT import questions from other topics or chapters.
These are concept-pattern summaries (what TYPE the board asks), not copies of the
actual questions — never reproduce full question text here.

### Concept: List and tuple operations
  Pattern: Assertion-Reason=3, MCQ=22, Output Prediction=4, Programming=1, Short Answer=10 | Marks: 1M=33, 2M=6, 3M=1 | Total: 40 questions
  [MCQ] [1M] [Easy] × 12
    → Core concept of List and tuple operations
  [MCQ] [1M] [Easy] × 10
    → Output/result interpretation for the current concept
  [Assertion-Reason] [1M] [Easy] × 3
    → Core concept of List and tuple operations
  [Output Prediction] [2M] [Easy] × 2
    → Output/result interpretation for the current concept
  [Short Answer] [2M] [Easy] × 3
    → Core concept of List and tuple operations
  [Short Answer] [1M] [Easy] × 3
    → True/False: core concept of List and tuple operations
  [Short Answer] [1M] [Easy] × 4
    → Core concept of List and tuple operations
  [Output Prediction] [1M] [Easy]
    → Output/result interpretation for the current concept
  [Programming] [2M] [Easy]
    → Core concept of List and tuple operations
  [Output Prediction] [3M] [Medium]
    → Output/result interpretation for the current concept


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IMPORTANCE ANALYSIS (allocate teaching time by this ranking)
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| Rank | Concept | Score | Times Tested | Total Marks | Recent Years | Priority |
|------|---------|-------|-------------|-------------|--------------|----------|
| 1 | List and tuple operations | 150 | 40 | 48M | 2026, 2025, 2024 | CRITICAL |

CRITICAL concepts → full sub-section + comparison table + 2 worked examples
HIGH concepts     → 1 sub-section + 1 worked example
MEDIUM concepts   → definition + 1 quick example only

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EXAMINER FINGERPRINT — TRAPS TO COVER INTERNALLY
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Use the exam-frequency input and actual previous-year questions to identify traps, marking points, and common mistakes. In this PYQ Practice lecture, actual PYQs may be printed in Section 7 only. Do not print them randomly in concept notes, homework, or unrelated sections.

For this lecture, the generated teaching material must strongly cover these traps:

No static trap list exists yet for "List and tuple operations". Self-generate 4–7 traps from:
- actual question patterns for List and tuple operations
- common wrong assumptions students make about this concept
- output-tracing traps
- syntax-vs-runtime traps
- comparison traps
- order/sequence traps

Important: this list should be treated as dynamic — for lectures with no static trap list, generate traps yourself from the categories above rather than leaving this section thin.
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YOUR TASK — Generate a complete classroom-ready teaching package
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Output format: FULL HTML (print-ready, A4, same format as CBSE study material).
Use the CSS classes below. NO plain Markdown — use HTML elements only.

HTML STRUCTURE TO GENERATE:

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  <h4>&#128214; Contents</h4>
  <!-- TOC links auto-built by JS above -->
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<!-- MAIN CONTENT -->
<div class="main-content">

Generate these sections in order (all inside the main-content div):

<h1 id="top">List and tuple operations PYQ — Lecture 11</h1>
<p style="text-align:center;color:#555;font-size:8.5pt;">CBSE | XII CS | Computational Thinking and Programming – 2 | 35 min</p>

<h2 id="s1">1. Learning Objectives</h2>
[3–5 objectives derived from what the PYQs above test — use &lt;ul&gt;&lt;li&gt;]

<h2 id="s2">2. 35-Minute Lecture Flow</h2>
[HTML table: Time | Activity | Teacher Action — include a PYQ discussion with full + compressed coverage]

<h2 id="s3">3. Quick Concept Recap</h2>
[Keep this section short. Do NOT reteach the full topic from scratch.
Include only the rules needed to solve the PYQs — i.e. the traps listed in the
EXAMINER FINGERPRINT section above (for this lecture: List and tuple operations).
Use .def-box and .key-box only. Add at most one tiny example if needed.
Do not include long theory, long programming tasks, or unrelated examples.]

<h2 id="s4">4. Examiner Tricks &amp; Common Mistakes</h2>
[One .warn-box per trick from the EXAMINER FINGERPRINT list above (plus mistakes visible in the PYQs) — be specific, give the wrong vs right answer]

<h2 id="s5">5. Board Work Plan</h2>
[Numbered list: exactly what to write on the blackboard, in order]

<h2 id="s6">6. Classroom Practice Questions</h2>
[Modelled on PYQ style. CRITICAL: every answer MUST be inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; — never expose the answer directly.

Practice questions must follow the difficulty and mark pattern of the actual PYQ pool.

For this topic:
* 3×1M MCQ
* 5×1M/2M Short Answer
* Include 2×3–5M programming practice (the PYQ pool contains long-answer/programming patterns)
* No HOTS question (the provided PYQs do not reveal a higher-order trap)

Every question must be based on one of the traps from Section 4 (EXAMINER FINGERPRINT).
Every answer must be hidden inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt;.

MCQ structure:
&lt;div class="mcq-box"&gt;
  &lt;b&gt;Q1.&lt;/b&gt; Question text?&lt;br&gt;
  &lt;ul class="options"&gt;
    &lt;li&gt;a) ...&lt;/li&gt;
    &lt;li&gt;b) ...&lt;/li&gt;
    &lt;li&gt;c) ...&lt;/li&gt;
    &lt;li&gt;d) ...&lt;/li&gt;
  &lt;/ul&gt;
  &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;
    &lt;ul class="options"&gt;
      &lt;li class="wrong"&gt;a) ... — reason why wrong&lt;/li&gt;
      &lt;li class="correct"&gt;b) ... ✓ — reason why correct&lt;/li&gt;
      ...
    &lt;/ul&gt;
  &lt;/details&gt;
&lt;/div&gt;
(Note: options list shown WITHOUT .correct/.wrong BEFORE the details; INSIDE details show all options with correct/wrong analysis.)

Short-answer structure:
&lt;div class="self-test-box"&gt;&lt;b&gt;Q4.&lt;/b&gt; Question&lt;br&gt;&lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;Full answer&lt;/details&gt;&lt;/div&gt;

Dynamic distribution rule:
* If actual PYQs are only 1M/2M, keep generated practice mostly 1M/2M.
* If actual PYQs include 3M/5M programming, include 3M/5M programming practice.
* Never force HOTS or programming questions when the provided PYQ pool does not support them.]

<h2 id="s7">7. PYQ Discussion / Full + Compressed Coverage (40 source questions)</h2>
[This source pool has 40 actual PYQs.
PYQ COVERAGE RULE:
  - If the PYQ pool has 15 or fewer questions, include and discuss ALL actual PYQs in Section 7.
  - Do not compress, replace, paraphrase, or skip any actual PYQ in a small pool.
  - This pool has more than 15 questions: fully discuss the highest-yield 15 and compactly
    list the rest with concept tested + exam trap.
  - Compression is allowed only when the source pool has more than 15 questions.
  - Never fabricate board years, marks, sections, or question text.
For every fully discussed actual PYQ include:
  year · marks · type · full question text · concept tested · model answer inside &lt;details&gt; · common mistake inside &lt;details&gt;
Order questions Easy to Tough; within difficulty, order 1 mark → 2 marks → 3 marks → 4/5 marks.
Use this structure for actual PYQ examples:
  Use this structure for each question:
  &lt;div class="pyq-box"&gt;
    &lt;div class="pyq-meta"&gt;[YEAR] · [X] Marks · [TYPE] · Section-[S]&lt;/div&gt;
    &lt;b&gt;Q.&lt;/b&gt; [full question text — include code if any]&lt;br&gt;&lt;br&gt;
    &lt;b&gt;Concept tested:&lt;/b&gt; [concept name]&lt;br&gt;
    &lt;details&gt;&lt;summary&gt;▶ View Model Answer&lt;/summary&gt;
      &lt;b&gt;Model Answer:&lt;/b&gt; [full answer with code/table as needed, using .kw/.bi/.st token spans in &lt;pre&gt;&lt;code&gt;]&lt;br&gt;
      &lt;b&gt;Common mistake:&lt;/b&gt; [what students get wrong — be specific]
    &lt;/details&gt;
  &lt;/div&gt;

For compressed representative questions, label them "Representative PYQ-pattern question", not as a real board question, and never show a fake year, marks, or section.]

<h2 id="s8">8. Student Notes (Copy-ready)</h2>
[Concise notes — every concept from PYQs — in .key-box and .def-box; self-check questions in .self-test-box with &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;answer&lt;/details&gt;]

<h2 id="s9">9. Homework</h2>
[Homework must follow the actual PYQ pattern for this topic:
- 3×1M MCQ
- 3×1M Short Answer
- 2×2M Short Answer only if useful for recap or trap correction
- Include 2×3–5M programming homework (the PYQ pool contains long-answer/programming patterns)
- Every homework question must map to one trap or pattern from Section 4 / Section 7.
Dynamic rule: if actual PYQs are only 1M/2M, homework stays mostly 1M/2M; if they include 3M/5M
programming, homework may include 3M/5M programming; never force unsupported marks or question types.
EVERY answer must be wrapped in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; inside .self-test-box or .mcq-box.]

<h2 id="s10">10. Exam Tips</h2>
[5 specific tips as .tip-box — derived from PYQ patterns for THIS topic only]

<h2 id="s11">11. Last-Minute Revision Cards</h2>
&lt;div class="card-grid"&gt;
[One .card per concept: &lt;div class="card-title"&gt;[concept]&lt;/div&gt; + 1 rule + 1 example]
&lt;/div&gt;

</div><!-- end .main-content -->
</body>
</html>

HARD OUTPUT RULES:
- Output ONLY the HTML document starting with &lt;!DOCTYPE html&gt;
- Do NOT wrap in markdown code fences
- Do NOT add explanatory text outside the HTML
- Use ONLY content from "List and tuple operations" — zero content from other topics
- PYQ lecture: fully discuss the highest-yield 15 and compactly list the rest with concept tested + exam trap; compression is allowed only because this pool exceeds 15
- Always finish the document completely through &lt;/html&gt;. If the answer is getting long, keep Sections 3 and 7 complete, then compact Sections 8–11 instead of truncating.
- If 15 or fewer PYQs are provided, include ALL actual PYQs in Section 7.
- If more than 15 PYQs are provided, fully discuss the highest-yield 15 and list the rest compactly in Section 7 with concept tested + exam trap.
- ANSWER HIDING (most important for student use):
    * Section 6 MCQs: options listed WITHOUT .correct/.wrong BEFORE details; full analysis only INSIDE &lt;details&gt;
    * Section 6 short/programming/HOTS questions: EVERY answer in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt;
    * Section 8 self-check and Section 9 homework: EVERY answer in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;
    * Section 7 PYQ Discussion / Full + Compressed Coverage: model answer + common mistake inside &lt;details&gt;&lt;summary&gt;▶ View Model Answer&lt;/summary&gt;
    * .pyq-box question text and concept tested stay visible outside &lt;details&gt;; only Model Answer + Common mistake are hidden inside &lt;details&gt;
    * The beforeprint JS already auto-opens all &lt;details&gt; for printing — never skip this feature
- INLINE CODE SIZE RULE:
    * Inline code (function/method names and short snippets relevant to "List and tuple operations") must appear almost the same size as surrounding normal text.
    * Do NOT use fixed 8.5pt size for all &lt;code&gt; elements.
    * Use code { font-size:0.95em; } for inline code.
    * Use pre { font-size:8.5pt; } for block code.
    * Use pre code { font-size:inherit; } so code blocks remain compact.
    * Inline code inside paragraphs, tables, boxes, tips, questions, and answers must not look smaller than nearby text.
- BOX / CLASS USAGE: this is a PYQ lecture, so .pyq-box/.pyq-meta are used as shown in Section 7 above (never in theory lectures).
- All content goes inside &lt;div class="main-content"&gt;
- The &lt;nav class="toc-sidebar"&gt; is already in the template — JS auto-builds TOC links
- Print buttons (.print-bar), including Read Mode, are in the template — DO NOT add them again; they auto-hide on print
- Include the full CSS and JS exactly as given (the CODE CSS already follows the INLINE CODE SIZE RULE above).