(self, cls)
return self.haslayer(cls)
cls in self" returns true if self has a layer which is an instance of cls.
cls in self" returns true if self has a layer which is an instance of cls.
cls in self returns true if self has a layer which is an instance of cls .
def __contains__(self, cls):
        """"cls in self" returns true if self has a layer which is an instance of cls."""
        return self.haslayer(cls)
def __contains__ ( self , cls ) : return self . haslayer ( cls )