For now, just a list, and we expect to encounter these. We will return to this post whenever we do to update it with examples.

• Misusing expressions as defaults for function arguments
• Using class variables incorrectly - Class variables are internally handled as dictionaries and follow Method Resolution Order (MRO)
• Specifying parameters incorrectly for an exception block - The proper way to catch multiple exceptions in an except statement is to specify the first parameter as a tuple containing all exceptions to be caught.
• Misunderstanding Python scope rules - Python scope resolution is based on what is known as the LEGB rule, which is shorthand for Local, Enclosing, Global, Built-in. Especially with lists, tricky. UnboundLocalError
• Modifying a list while iterating over it - List comprehensions are particularly useful for avoiding this specific problem
• Confusing how Python binds variables in closures - Python’s late binding behavior says that the values of variables used in closures are looked up at the time the inner function is called.

        >>> def create_multipliers():
        ...     return [lambda x : i * x for i in range(5)]
        >>> for multiplier in create_multipliers():
        ...     print multiplier(2)
        ...
        8
        8
        8
        8
        8

    The solution to this common Python problem is a bit of a hack:

        >>> def create_multipliers():
        ...     return [lambda x, i=i : i * x for i in range(5)]
        ...
        >>> for multiplier in create_multipliers():
        ...     print multiplier(2)
        ...
        0
        2
        4
        6
        8
    

• Creating circular module dependencies
• Name clashing with Python Standard Library modules
• Misusing the __del__ method

...

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