def test_function_series2():
 class my_function2(Function, ):
  def fdiff(self, argindex=1):
   return (- sin(self.args[0]))
  @classmethod
  def eval(cls, arg):
   arg = sympify(arg)
   if (arg == 0):
    return sympify(1)
 assert (my_function2(x).series(x, 0, 10) == cos(x).series(x, 0, 10))

def test_function_series2 ( ) : class my_function2 ( Function , ) : def fdiff ( self , argindex = 1 ) : return ( - sin ( self . args [ 0 ] ) ) @ classmethod def eval ( cls , arg ) : arg = sympify ( arg ) if ( arg == 0 ) : return sympify ( 1 ) assert ( my_function2 ( x ) . series ( x , 0 , 10 ) == cos ( x ) . series ( x , 0 , 10 ) )
create our new "cos" function .