'Even number predicate.
``ask(Q.even(x))`` is true iff ``x`` belongs to the set of even
integers.
Examples
>>> from sympy import Q, ask, pi
>>> ask(Q.even(0))
True
>>> ask(Q.even(2))
True
>>> ask(Q.even(3))
False
>>> ask(Q.even(pi))
False'

@predicate_memo
def even(self):

    return Predicate('even')
