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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def to_iter(obj):
 """Convert an object to a list if it is not already an iterable. Nones are returned unaltered. This is an awful function that proliferates an explosion of types, please do not use anymore. """

    if isinstance(obj, type(None)):
        return None
    elif isinstance(obj, six.string_types):
        return [obj]
    else:
        # Nesting here since symmetry is broken in isinstance checks.
        # Strings are iterables in python 3, so the relative order of if statements is important.
        if isinstance(obj, collections.Iterable):
            return obj
        else:
            return [obj]