<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def ifelse(self, node):
        'ifelse = "if" expr "then" expr "else" expr'
        _, cond, _, cons, _, alt = node
        return self.eval(cons) if self.eval(cond) else self.eval(alt)