def assert_false(expr, msg_fmt="{msg}"):
    """Fail the test unless the expression is falsy.

    >>> assert_false("")
    >>> assert_false("Hello World!")
    Traceback (most recent call last):
        ...
    AssertionError: 'Hello World!' is not falsy

    The following msg_fmt arguments are supported:
    * msg - the default error message
    * expr - tested expression
    """

    if expr:
        msg = "{!r} is not falsy".format(expr)
        fail(msg_fmt.format(msg=msg, expr=expr))
def assert_false ( expr , msg_fmt = "{msg}" ) : if expr : msg = "{!r} is not falsy" . format ( expr ) fail ( msg_fmt . format ( msg = msg , expr = expr ) )
Fail the test unless the expression is falsy.

    >>> assert_false("")
    >>> assert_false("Hello World!")
    Traceback (most recent call last):
        ...
    AssertionError: 'Hello World!' is not falsy

    The following msg_fmt arguments are supported:
    * msg - the default error message
    * expr - tested expression