Django错误 - AttributeError：'CourseOverview'对象没有属性'start_datetime_text'

我一直试图让这个主题适用于Open edX（基于Django），我在主管日志中收到此错误 -

AttributeError: 'CourseOverview' object has no attribute 'start_datetime_text'

整个错误就是这个 -

May 14 11:43:36 ip-172-26-15-154 [service_variant=lms][django.request][env:sandbox] ERROR [ip-172-26-15-154  20450] [base.py:256] - Internal Server Error: /
Traceback (most recent call last):
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/django/utils/decorators.py", line 145, in inner
    return func(*args, **kwargs)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/django/utils/decorators.py", line 110, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/edx/app/edxapp/edx-platform/common/djangoapps/util/cache.py", line 78, in wrapper
    response = view_func(request, *args, **kwargs)
  File "/edx/app/edxapp/edx-platform/lms/djangoapps/branding/views.py", line 94, in index
    return student.views.index(request, user=request.user)
  File "/edx/app/edxapp/edx-platform/common/djangoapps/student/views.py", line 221, in index
    return render_to_response('index.html', context)
  File "/edx/app/edxapp/edx-platform/common/djangoapps/edxmako/shortcuts.py", line 198, in render_to_response
    return HttpResponse(render_to_string(template_name, dictionary, context_instance, namespace, request), **kwargs)
  File "/edx/app/edxapp/edx-platform/common/djangoapps/edxmako/shortcuts.py", line 188, in render_to_string
    return template.render_unicode(**context_dictionary)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/template.py", line 454, in render_unicode
    as_unicode=True)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 829, in _render
    **_kwargs_for_callable(callable_, data))
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 864, in _render_context
    _exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 890, in _exec_template
    callable_(context, *args, **kwargs)
  File "/tmp/mako_lms/c11f9c5f254718c770fcf021e95ac093/main.html.py", line 286, in render_body
    __M_writer(filters.decode.utf8(self.body()))
  File "/tmp/mako_lms/c11f9c5f254718c770fcf021e95ac093/marvel-theme-eucalyptus/lms/templates/index.html.py", line 54, in render_body
    runtime._include_file(context, (courses_list), _template_uri)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 752, in _include_file
    callable_(ctx, **_kwargs_for_include(callable_, context._data, **kwargs))
  File "/tmp/mako_lms/c11f9c5f254718c770fcf021e95ac093/marvel-theme-eucalyptus/lms/templates/courses_list.html.py", line 44, in render_body
    runtime._include_file(context, u'course.html', _template_uri, course=course)
  File "/edx/app/edxapp/venvs/edxapp/local/lib/python2.7/site-packages/mako/runtime.py", line 752, in _include_file
    callable_(ctx, **_kwargs_for_include(callable_, context._data, **kwargs))
  File "/tmp/mako_lms/c11f9c5f254718c770fcf021e95ac093/marvel-theme-eucalyptus/lms/templates/course.html.py", line 60, in render_body
    __M_writer(filters.html_escape(filters.decode.utf8(course.start_datetime_text())))
AttributeError: 'CourseOverview' object has no attribute 'start_datetime_text'

有问题的文件（提供错误的文件 - course.html.py）在这里https://pastebin.com/0S79hhDa