(self, name)
return self.get(name) is not None
Return true if the message contains the header.
Return true if the message contains the header.
Return true if the message contains the header .
def __contains__(self, name):
        """Return true if the message contains the header."""
        return self.get(name) is not None
def __contains__ ( self , name ) : return self . get ( name ) is not None