def METHOD_NAME(self, p):
    """
    expression : expression PLUS expression
              | expression MINUS expression
              | expression TIMES expression
              | expression DIVIDE expression
              | expression EXP expression
    """
    # print [repr(p[i]) for i in range(0,4)]
    if p[2] == '+':
        p[0] = p[1] + p[3]
    elif p[2] == '-':
        p[0] = p[1] - p[3]
    elif p[2] == '*':
        p[0] = p[1] * p[3]
    elif p[2] == '/':
        p[0] = p[1] / p[3]
    elif p[2] == '**':
        p[0] = p[1] ** p[3]