def keys(self):
        """ Return all the keys that represent possible attributes and
        children.

        :return: list of keys
        """
        keys = ['text']
        keys.extend([n for (n, t, r) in self.c_attributes.values()])
        keys.extend([v[0] for v in self.c_children.values()])
        return keys
def keys ( self ) : keys = [ 'text' ] keys . extend ( [ n for ( n , t , r ) in self . c_attributes . values ( ) ] ) keys . extend ( [ v [ 0 ] for v in self . c_children . values ( ) ] ) return keys
Return all the keys that represent possible attributes and
        children.

        :return: list of keys