def by_contract_id(self,contract_id: str) -> ContractItemRequestBuilder:
        """
        Provides operations to manage the collection of contract entities.
        param contract_id: The unique identifier of contract
        Returns: ContractItemRequestBuilder
        """
        if contract_id is None:
            raise TypeError("contract_id cannot be null.")
        from .item.contract_item_request_builder import ContractItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["contract%2Did"] = contract_id
        return ContractItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the collection of contract entities.
        param contract_id: The unique identifier of contract
        Returns: ContractItemRequestBuilder
        
msgraph/generated/contracts/contracts_request_builder.py