def _meijerint_definite_2(f, x):
    # This function does preparation for (2), calls
    # _meijerint_definite_3 for (2) and (3) combined.

    # use a positive dummy - we integrate from 0 to oo
    # XXX if a nonnegative symbol is used there will be test failures
    dummy = _dummy('x', 'meijerint-definite2', f, positive=True)
    f = f.subs(x, dummy)
    x = dummy

    if f == 0:
        return S(0), True

    for g, explanation in _guess_expansion(f, x):
        _debug('Trying', explanation)
        res = _meijerint_definite_3(g, x)
        if res:
            return res
Try to integrate f dx from zero to infinty.
dataset/ETHPy150Open sympy/sympy/sympy/integrals/meijerint.py/_meijerint_definite_2