[srcco.de] TemplateModule object' has no attribute 'open_graph_metadata'

[Suleman-Elahi]

Faced the above error about unhandled exception after installing the Srcco.de theme.

After installing the theme when I issue 'build' command, the same errors is shown.

(nikola) PS D:\nikola\site> nikola theme -i srcco.de
[2023-01-07 12:50:33] INFO: theme: Downloading 'https://themes.getnikola.com/v7/srcco.de.zip'
[2023-01-07 12:50:33] INFO: theme: Extracting 'srcco.de' into themes/
[2023-01-07 12:50:33] INFO: theme: Remember to set THEME="srcco.de" in conf.py to use this theme.
(nikola) PS D:\nikola\site> nikola build
Scanning posts........done!
.  render_galleries:output\galleries\index.html
.  render_galleries:output\galleries\rss.xml
.  render_galleries:output\galleries\demo\index.html
TaskError - taskid:render_galleries:output\galleries\demo\index.html
PythonAction Error
Traceback (most recent call last):
  File "D:\nikola\lib\site-packages\doit\action.py", line 461, in execute
    returned_value = self.py_callable(*self.args, **kwargs)
  File "D:\nikola\lib\site-packages\nikola\plugins\task\galleries.py", line 717, in render_gallery_index
    self.site.render_template(template_name, output_name, context)
  File "D:\nikola\lib\site-packages\nikola\nikola.py", line 1487, in render_template
    data = self.template_system.render_template(
  File "D:\nikola\lib\site-packages\nikola\plugins\template\jinja.py", line 98, in render_template
    data = template.render(**context)
  File "D:\nikola\lib\site-packages\jinja2\environment.py", line 1301, in render
    self.environment.handle_exception()
  File "D:\nikola\lib\site-packages\jinja2\environment.py", line 936, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "D:\nikola\lib\site-packages\nikola\data\themes\base-jinja\templates\gallery.tmpl", line 5, in top-level template code
    {% import 'post_helper.tmpl' as post_helper with context %}
  File "themes\srcco.de\templates\base.tmpl", line 9, in top-level template code
    {% block extra_head %}
  File "D:\nikola\lib\site-packages\nikola\data\themes\base-jinja\templates\gallery.tmpl", line 77, in block 'extra_head'    {{ post_helper.open_graph_metadata(post) }}
  File "D:\nikola\lib\site-packages\jinja2\utils.py", line 83, in from_obj
    if hasattr(obj, "jinja_pass_arg"):
jinja2.exceptions.UndefinedError: 'jinja2.environment.TemplateModule object' has no attribute 'open_graph_metadata'

########################################
render_galleries:output\galleries\demo\index.html <stdout>:

How to fix this.