:return: the value wrapped in a list unless it is already iterable (and not a dict);
    if so, empty values will be filtered out by default, and an empty list is returned.

def wrap_value(value, include_empty=False):
    """
    :return: the value wrapped in a list unless it is already iterable (and not a dict);
    if so, empty values will be filtered out by default, and an empty list is returned.
    """

    if value is None:
        return [None] if include_empty else []
    elif hasattr(value, '__len__') and len(value) == 0:
        return [value] if include_empty else []
    elif isinstance(value, _wrap_types):
        return [value]
    elif not hasattr(value, '__iter__'):
        return [value]

    return value if include_empty else filter_empty(value, [])