small improvement in add_nml_channel_to_nml_cell_file

Author: Jaquier Aurélien Tristan

bluepyopt/neuroml/biophys.py

@@ -192,15 +192,15 @@ def add_nml_channel_to_nml_cell_file(
         channel_nml2_file = f"{channel_name}.channel.nml"
 
     if channel_nml2_file not in included_channels:
-        nml_mech_dir = get_nml_mech_dir()
         channel_new_path = Path(channel_dir) / channel_nml2_file
         cell_doc.includes.append(neuroml.IncludeType(href=channel_new_path))
 
         # for some reason, pynml cannot accept absolute paths in IncludeType,
         # so copy paste files in current directory for the simulation to work
         if not skip_channels_copy:
             Path(channel_dir).mkdir(exist_ok=True)
-            channel_path = Path(nml_mech_dir) / channel_nml2_file
+            nml_mech_dir = Path(get_nml_mech_dir())
+            channel_path = nml_mech_dir / channel_nml2_file
             if channel_path.is_file():
                 shutil.copy(channel_path, channel_new_path)