def is_pseq(arg):
    '''
    is_pseq(arg) yields True if arg is a persistent vector, a persistent list, a tuple, or a numpy
      array with its writeable flag off.
    '''
    if is_nparray(arg): return arg.flags['WRITEABLE'] == False
    return isinstance(arg, (tuple_type, pyr.PVector, pyr.PList))
def is_pseq ( arg ) : if is_nparray ( arg ) : return arg . flags [ 'WRITEABLE' ] == False return isinstance ( arg , ( tuple_type , pyr . PVector , pyr . PList ) )
is_pseq(arg) yields True if arg is a persistent vector, a persistent list, a tuple, or a numpy
      array with its writeable flag off.