'x.__isub__(y) <=> x-=y'

def __isub__(self, other):

    if (not self.writable):
        raise ValueError('trying    to    subtract    from    a    readonly    NDArray')
    if isinstance(other, NDArray):
        return broadcast_sub(self, other, out=self)
    elif isinstance(other, numeric_types):
        return _internal._minus_scalar(self, float(other), out=self)
    else:
        raise TypeError(('type    %s    not    supported' % str(type(other))))
