@utilities.arguments_not_none<EOL><INDENT>def update_gradebook_column(self, gradebook_column_form):<DEDENT>
collection = JSONClientValidated('<STR_LIT>',<EOL>collection='<STR_LIT>',<EOL>runtime=self._runtime)<EOL>if not isinstance(gradebook_column_form, ABCGradebookColumnForm):<EOL><INDENT>raise errors.InvalidArgument('<STR_LIT>')<EOL><DEDENT>if not gradebook_column_form.is_for_update():<EOL><INDENT>raise errors.InvalidArgument('<STR_LIT>')<EOL><DEDENT>try:<EOL><INDENT>if self._forms[gradebook_column_form.get_id().get_identifier()] == UPDATED:<EOL><INDENT>raise errors.IllegalState('<STR_LIT>')<EOL><DEDENT><DEDENT>except KeyError:<EOL><INDENT>raise errors.Unsupported('<STR_LIT>')<EOL><DEDENT>if not gradebook_column_form.is_valid():<EOL><INDENT>raise errors.InvalidArgument('<STR_LIT>')<EOL><DEDENT>old_column = collection.find_one({"<STR_LIT>": gradebook_column_form._my_map['<STR_LIT>']})<EOL>if old_column['<STR_LIT>'] != gradebook_column_form._my_map['<STR_LIT>']:<EOL><INDENT>if self._has_entries(gradebook_column_form.id_):<EOL><INDENT>raise errors.IllegalState('<STR_LIT>' +<EOL>'<STR_LIT>')<EOL><DEDENT><DEDENT>collection.save(gradebook_column_form._my_map)<EOL>self._forms[gradebook_column_form.get_id().get_identifier()] = UPDATED<EOL>return objects.GradebookColumn(<EOL>osid_object_map=gradebook_column_form._my_map,<EOL>runtime=self._runtime,<EOL>proxy=self._proxy)<EOL>
Updates an existing gradebook column.

        arg:    gradebook_column_form
                (osid.grading.GradebookColumnForm): the form containing
                the elements to be updated
        raise:  IllegalState - ``gradebook_column_form`` already used in
                an update transaction
        raise:  InvalidArgument - the form contains an invalid value
        raise:  NullArgument - ``gradebook_column_form`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        raise:  Unsupported - ``gradebook_column_form`` did not
                originate from
                ``get_gradebook_column_form_for_update()``
        *compliance: mandatory -- This method must be implemented.*