'Return True/False for cw/ccw orientation.
Examples
>>> from sympy import Point, Polygon
>>> a, b, c = [Point(i) for i in [(0, 0), (1, 1), (1, 0)]]
>>> Polygon._isright(a, b, c)
True
>>> Polygon._isright(a, c, b)
False'

@staticmethod
def _isright(a, b, c):

    ba = (b - a)
    ca = (c - a)
    t_area = simplify(((ba.x * ca.y) - (ca.x * ba.y)))
    res = t_area.is_nonpositive
    if (res is None):
        raise ValueError("Can't    determine    orientation")
    return res
