add assert info

Author: wz

data_set/split_data.py

@@ -21,7 +21,8 @@ def main():
     cwd = os.getcwd()
     data_root = os.path.join(cwd, "flower_data")
     origin_flower_path = os.path.join(data_root, "flower_photos")
-    assert os.path.exists(origin_flower_path)
+    assert os.path.exists(origin_flower_path), "path '{}' does not exist.".format(origin_flower_path)
+
     flower_class = [cla for cla in os.listdir(origin_flower_path)
                     if os.path.isdir(os.path.join(origin_flower_path, cla))]