def by_mobile_app_category_id(self,mobile_app_category_id: str) -> MobileAppCategoryItemRequestBuilder:
        """
        Provides operations to manage the mobileAppCategories property of the microsoft.graph.deviceAppManagement entity.
        param mobile_app_category_id: The unique identifier of mobileAppCategory
        Returns: MobileAppCategoryItemRequestBuilder
        """
        if mobile_app_category_id is None:
            raise TypeError("mobile_app_category_id cannot be null.")
        from .item.mobile_app_category_item_request_builder import MobileAppCategoryItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["mobileAppCategory%2Did"] = mobile_app_category_id
        return MobileAppCategoryItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the mobileAppCategories property of the microsoft.graph.deviceAppManagement entity.
        param mobile_app_category_id: The unique identifier of mobileAppCategory
        Returns: MobileAppCategoryItemRequestBuilder
        
msgraph/generated/device_app_management/mobile_app_categories/mobile_app_categories_request_builder.py