Macro Rendering Error

File: external-links.md

TypeError: 'NoneType' object is not iterable

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.11.11/x64/lib/python3.11/site-packages/mkdocs_macros/plugin.py", line 688, in render
    return md_template.render(**page_variables)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.11/x64/lib/python3.11/site-packages/jinja2/environment.py", line 1295, in render
    self.environment.handle_exception()
  File "/opt/hostedtoolcache/Python/3.11.11/x64/lib/python3.11/site-packages/jinja2/environment.py", line 942, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "<template>", line 35, in top-level template code
TypeError: 'NoneType' object is not iterable