def contains_key(self, key):
        """
        Determines whether this map contains an entry with the key.

        **Warning: This method uses __hash__ and __eq__ methods of binary form of the key, not the actual implementations
        of __hash__ and __eq__ defined in key's class.**

        :param key: (object), the specified key.
        :return: (bool), ``true`` if this map contains an entry for the specified key.
        """
        check_not_none(key, "key can't be None")
        key_data = self._to_data(key)
        return self._contains_key_internal(key_data)
def contains_key ( self , key ) : check_not_none ( key , "key can't be None" ) key_data = self . _to_data ( key ) return self . _contains_key_internal ( key_data )
Determines whether this map contains an entry with the key.

        **Warning: This method uses __hash__ and __eq__ methods of binary form of the key, not the actual implementations
        of __hash__ and __eq__ defined in key's class.**

        :param key: (object), the specified key.
        :return: (bool), ``true`` if this map contains an entry for the specified key.