variable_declaration_list \
            : variable_declaration
            | variable_declaration_list COMMA variable_declaration

def p_variable_declaration_list(self, p):
        """
        variable_declaration_list \
            : variable_declaration
            | variable_declaration_list COMMA variable_declaration
        """
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[1].append(p[3])
            p[0] = p[1]