def by_user_source_id(self,user_source_id: str) -> UserSourceItemRequestBuilder:
        """
        Provides operations to manage the userSources property of the microsoft.graph.security.ediscoveryCustodian entity.
        param user_source_id: The unique identifier of userSource
        Returns: UserSourceItemRequestBuilder
        """
        if user_source_id is None:
            raise TypeError("user_source_id cannot be null.")
        from .item.user_source_item_request_builder import UserSourceItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["userSource%2Did"] = user_source_id
        return UserSourceItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the userSources property of the microsoft.graph.security.ediscoveryCustodian entity.
        param user_source_id: The unique identifier of userSource
        Returns: UserSourceItemRequestBuilder
        
msgraph/generated/security/cases/ediscovery_cases/item/custodians/item/user_sources/user_sources_request_builder.py