def by_external_activity_id(self,external_activity_id: str) -> ExternalActivityItemRequestBuilder:
        """
        Provides operations to manage the activities property of the microsoft.graph.externalConnectors.externalItem entity.
        param external_activity_id: The unique identifier of externalActivity
        Returns: ExternalActivityItemRequestBuilder
        """
        if external_activity_id is None:
            raise TypeError("external_activity_id cannot be null.")
        from .item.external_activity_item_request_builder import ExternalActivityItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["externalActivity%2Did"] = external_activity_id
        return ExternalActivityItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the activities property of the microsoft.graph.externalConnectors.externalItem entity.
        param external_activity_id: The unique identifier of externalActivity
        Returns: ExternalActivityItemRequestBuilder
        
msgraph/generated/connections/item/items/item/activities/activities_request_builder.py