'Returns the last non-zero monomial of ``f``.
Examples
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).EM()
x**0*y**1'

def EM(f, order=None):

    return Monomial(f.monoms(order)[(-1)], f.gens)
