import types


def is_object(obj):
    """Returns True is obj is a reference to an object instance.

    >>> is_object(1)
    True

    >>> is_object(object())
    True

    >>> is_object(lambda x: 1)
    False
    """
    return (isinstance(obj, object) and
            type(obj) is not type and
            type(obj) is not types.FunctionType)