code: def remove_collection(self, first_arg, sec_arg, third_arg, fourth_arg=None, commit_msg=None):
          
          if fourth_arg is None:
              collection_id, branch_name, author = first_arg, sec_arg, third_arg
              gh_user = branch_name.split('_collection_')[0]
              parent_sha = self.get_master_sha()
          else:
              gh_user, collection_id, parent_sha, author = first_arg, sec_arg, third_arg, fourth_arg
          if commit_msg is None:
              commit_msg = "Delete Collection '%s' via OpenTree API" % collection_id
          return self._remove_document(gh_user, collection_id, parent_sha, author, commit_msg)
docs: Remove a collection
          Given a collection_id, branch and optionally an
          author, remove a collection on the given branch
          and attribute the commit to author.
          Returns the SHA of the commit on branch.