Method one

lib/sqlalchemy/engine/result.py:1087–1118

Return exactly one row or raise an exception. Raises :class:`_exc.NoResultFound` if the result returns no rows, or :class:`_exc.MultipleResultsFound` if multiple rows would be returned. .. note:: This method returns one **row**, e.g. tuple, by default. T

(self)

        )

    def one(self) -> Row[Unpack[_Ts]]:
        """Return exactly one row or raise an exception.

        Raises :class:`_exc.NoResultFound` if the result returns no
        rows, or :class:`_exc.MultipleResultsFound` if multiple rows
        would be returned.

        .. note::  This method returns one **row**, e.g. tuple, by default.
           To return exactly one single scalar value, that is, the first
           column of the first row, use the
           :meth:`_engine.Result.scalar_one` method, or combine
           :meth:`_engine.Result.scalars` and
           :meth:`_engine.Result.one`.

        .. versionadded:: 1.4

        :return: The first :class:`_engine.Row`.

        :raises: :class:`.MultipleResultsFound`, :class:`.NoResultFound`

        .. seealso::

            :meth:`_engine.Result.first`

            :meth:`_engine.Result.one_or_none`

            :meth:`_engine.Result.scalar_one`

        """
        return self._only_one_row(
            raise_for_second_row=True, raise_for_none=True, scalar=False
        )

    # special case to handle mypy issue:
    # https://github.com/python/mypy/issues/20651