Everything Python works with is a value, and every value has a type. A name is a label that points at a value. Assignment with = attaches the label. It never copies anything.

a = [1, 2]
b = a        # same list, two names
b.append(3)
print(a)     # [1, 2, 3]
a = "text"   # a now points elsewhere
print(b)     # still [1, 2, 3]

• type(x).__name__ gives the name of its type.
• repr(x) gives an unambiguous text form, with quotes around strings.
• None is the value that means "nothing here".
• == compares values. is asks whether two names point at the same object, so keep it for None.

The right side of an assignment runs first, which is why x, y = y, x swaps two names without a temporary variable.

Write describe(value) returning "<type name>: <repr of value>", and swap(a, b) returning (b, a). At the end of the file, print describe(42).

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