def __init__(self,default=(0,0),length=None,**params):
        """
        Initialize a tuple parameter with a fixed length (number of
        elements).  The length is determined by the initial default
        value, if any, and must be supplied explicitly otherwise.  The
        length is not allowed to change after instantiation.
        """
        super(Tuple,self).__init__(default=default,**params)
        if length is None and default is not None:
            self.length = len(default)
        elif length is None and default is None:
            raise ValueError("%s: length must be specified if no default is supplied." %
                             (self.name))
        else:
            self.length = length
        self._validate(default)
def __init__ ( self , default = ( 0 , 0 ) , length = None , ** params ) : super ( Tuple , self ) . __init__ ( default = default , ** params ) if length is None and default is not None : self . length = len ( default ) elif length is None and default is None : raise ValueError ( "%s: length must be specified if no default is supplied." % ( self . name ) ) else : self . length = length self . _validate ( default )
Initialize a tuple parameter with a fixed length (number of
        elements).  The length is determined by the initial default
        value, if any, and must be supplied explicitly otherwise.  The
        length is not allowed to change after instantiation.