py: Use mp_arg_check_num in more places.

Updated functions now do proper checking that n_kw==0, and are simpler
because they don't have to explicitly raise an exception.  Down side is
that the error messages no longer include the function name, but that's
acceptable.

Saves order 300 text bytes on x64 and ARM.

py/objcomplex.c

@@ -34,6 +34,7 @@
 #include "obj.h"
 #include "parsenum.h"
 #include "runtime0.h"
+#include "runtime.h"
 
 #if MICROPY_ENABLE_FLOAT
 
@@ -74,7 +75,7 @@ STATIC void complex_print(void (*print)(void *env, const char *fmt, ...), void *
 }
 
 STATIC mp_obj_t complex_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
-    // TODO check n_kw == 0
+    mp_arg_check_num(n_args, n_kw, 0, 2, false);
 
     switch (n_args) {
         case 0:
@@ -94,7 +95,8 @@ STATIC mp_obj_t complex_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const
                 return mp_obj_new_complex(mp_obj_get_float(args[0]), 0);
             }
 
-        case 2: {
+        case 2:
+        default: {
             mp_float_t real, imag;
             if (MP_OBJ_IS_TYPE(args[0], &mp_type_complex)) {
                 mp_obj_complex_get(args[0], &real, &imag);
@@ -112,9 +114,6 @@ STATIC mp_obj_t complex_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const
             }
             return mp_obj_new_complex(real, imag);
         }
-
-        default:
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "complex takes at most 2 arguments, %d given", n_args));
     }
 }