def p_case_clauses(self, p):
        """case_clauses : case_clause
                        | case_clauses case_clause
        """
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[1].append(p[2])
            p[0] = p[1]
def p_case_clauses ( self , p ) : if len ( p ) == 2 : p [ 0 ] = [ p [ 1 ] ] else : p [ 1 ] . append ( p [ 2 ] ) p [ 0 ] = p [ 1 ]
case_clauses : case_clause
                        | case_clauses case_clause