'Args:
horiz (bool): use horizontal flip.
vert (bool): use vertical flip.
prob (float): probability of flip.'

def __init__(self, horiz=False, vert=False, prob=0.5):

    super(Flip, self).__init__()
    if (horiz and vert):
        raise ValueError('Cannot    do    both    horiz    and    vert.    Please    use    two    Flip    instead.')
    elif horiz:
        self.code = 1
    elif vert:
        self.code = 0
    else:
        raise ValueError('Are    you    kidding?')
    self.prob = prob
    self._init()
