A big mess of changes

[MaybeJustJames]

Chapter 1: Introduction

• Briefly describe the help() functions

Chapter 2: Variables and operators

• Organisation
• Remove mention of the identity operator (is) because it's subtle in ways that aren't appropriate for beginners. This does unfortunately mean we're doing inappropriate comparisons to None but I think that's a small price to pay.

Chapter 4: Conditions

• Formatting and flesh out text
• Add a section asking students to find an indentation bug
• Merge sections describing else and elif and flesh out the explanation with an example in English and pseudocode

Chapter 5: Lists, Tuples, and Sets

• Minor text corrections and flesh out a little
• Avoid mentioning "dictionary"
• Summarise in intro with a table rather than text
• Add a question for students about creating an empty set(). This is meant for them to discover a pitfall. The correct answer is set(), not {} which is a dict.
• Add section on unpacking and the unpacking operator *

Chapter 6: Loops

• Flesh out explanation of loops where students were confused in previous teaching sessions.
• Explain loop iteration with loop unrolling
• Emphasise reading for as for-each
• Subtly introduce iterables
• Emphasise enumerate() over raw indexing with a guided "example problem".
• Introduce the conventional use of _
• Highlight the danger of while
• Add an exercise demonstrating the danger of while.

Chapter 8: Dictionaries

• Flesh out and correct text a little
• Describe the correct way to loop over the keys in a dictionary
• Formatting

Chapter 9: Files

• Formatting
• Use context managers (with) everywhere
• Describe why with is better than manually calling open()/close()

Chapter 10: Functions

• Formatting
• Fleshed out and corrected text a little
• Cover an error students might encounter writing and using their own functions
• Restructure and flesh out section titled "Flexibility in functions"
  • Reference back to chapter 5 unpacking and *
  • Talk about keyword arguments
• Add a section with some advice on writing functions

Solutions

• Updated in line with the above changes

[MaybeJustJames]

There are some grammatical errors I'll need to fix. But these are essentially the changes

[MaybeJustJames]

@tmuylder This PR can be closed