def declaration(function):
    '''
    Declare abstract function. 
    
    Requires function to be empty except for docstring describing semantics.
    To apply function, first argument must come with implementation of semantics.
    '''
    function,name=_strip_function(function)
    if not function.__code__.co_code in [empty_function.__code__.co_code, doc_string_only_function.__code__.co_code]: 
        raise ValueError('Declaration requires empty function definition')
    def not_implemented_function(*args,**kwargs):
        raise ValueError('Argument \'{}\' did not specify how \'{}\' should act on it'.format(args[0],name))
    not_implemented_function.__qualname__=not_implemented_function.__name__ 
    return default(not_implemented_function,name=name)
def declaration(function):
    
    function,name=_strip_function(function)
    if not function.__code__.co_code in [empty_function.__code__.co_code, doc_string_only_function.__code__.co_code]: 
        raise ValueError('Declaration requires empty function definition')
    def not_implemented_function(*args,**kwargs):
        raise ValueError('Argument \'{}\' did not specify how \'{}\' should act on it'.format(args[0],name))
    not_implemented_function.__qualname__=not_implemented_function.__name__ 
    return default(not_implemented_function,name=name)
def declaration ( function ) : function , name = _strip_function ( function ) if not function . __code__ . co_code in [ empty_function . __code__ . co_code , doc_string_only_function . __code__ . co_code ] : raise ValueError ( 'Declaration requires empty function definition' ) def not_implemented_function ( * args , * * kwargs ) : raise ValueError ( 'Argument \'{}\' did not specify how \'{}\' should act on it' . format ( args [ 0 ] , name ) ) not_implemented_function . __qualname__ = not_implemented_function . __name__ return default ( not_implemented_function , name = name )
Declare abstract function. 
    
    Requires function to be empty except for docstring describing semantics.
    To apply function, first argument must come with implementation of semantics.
Declare abstract function . Requires function to be empty except for docstring describing semantics . To apply function first argument must come with implementation of semantics .