def rsub(self, rhs):
 if isinstance(rhs, variable.Variable):
  return Sub()(rhs, self)
 _check_constant_type(rhs)
 return SubFromConstant(rhs)(self)

def rsub ( self , rhs ) : if isinstance ( rhs , variable . Variable ) : return Sub ( ) ( rhs , self ) _check_constant_type ( rhs ) return SubFromConstant ( rhs ) ( self )
element-wise subtraction .