Update src/wireviz/wireviz.py (#383)

Raising TypeError is better than assert. (Black reformatted)

Co-authored-by: Andreas Motl <andreas.motl@panodata.org>

src/wireviz/wireviz.py

@@ -88,9 +88,10 @@ def parse(
         raise Exception("No output formats or return types specified")
 
     yaml_data, yaml_file = _get_yaml_data_and_path(inp)
-    assert isinstance(
-        yaml_data, dict
-    ), f"Expected a dict as top-level YAML input, but got: {type(yaml_data)}"
+    if not isinstance(yaml_data, dict):
+        raise TypeError(
+            f"Expected a dict as top-level YAML input, but got: {type(yaml_data)}"
+        )
     if output_formats:
         # need to write data to file, determine output directory and filename
         output_dir = _get_output_dir(yaml_file, output_dir)