while_statement : WHILE LPAREN cond RPAREN whilecontent_statement

def p_while_statement(self, p):
        'while_statement : WHILE LPAREN cond RPAREN whilecontent_statement'
        p[0] = WhileStatement(p[3], p[5], lineno=p.lineno(1))
        p.set_lineno(0, p.lineno(1))