def is_collection(item):
    """
    Returns True if the item is a collection class: list, tuple, set, frozenset
    or any other class that resembles one of these (using abstract base classes).

    >>> is_collection(0)
    False
    >>> is_collection(0.1)
    False
    >>> is_collection('')
    False
    >>> is_collection({})
    False
    >>> is_collection({}.keys())
    True
    >>> is_collection([])
    True
    >>> is_collection(())
    True
    >>> is_collection(set())
    True
    >>> is_collection(frozenset())
    True
    >>> from coaster.utils import InspectableSet
    >>> is_collection(InspectableSet({1, 2}))
    True
    """
    return not isinstance(item, six.string_types) and isinstance(item, (collections.Set, collections.Sequence))
Returns True if the item is a collection class: list, tuple, set, frozenset
    or any other class that resembles one of these (using abstract base classes).

    >>> is_collection(0)
    False
    >>> is_collection(0.1)
    False
    >>> is_collection('')
    False
    >>> is_collection({})
    False
    >>> is_collection({}.keys())
    True
    >>> is_collection([])
    True
    >>> is_collection(())
    True
    >>> is_collection(set())
    True
    >>> is_collection(frozenset())
    True
    >>> from coaster.utils import InspectableSet
    >>> is_collection(InspectableSet({1, 2}))
    True