oplus/epm/queryset.py
def one(self, filter_by=None):
        """
        Parameters
        ----------
        filter_by: callable, default None
            Callable must take one argument (a record of table), and return True to keep record, or False to skip it.
            Example : .one(lambda x: x.name == "my_name").
            If None, records are not filtered.

        Returns
        -------
        Record instance if one and only one record is found. Else raises.

        Raises
        ------
        RecordDoesNotExistError if no record is found
        MultipleRecordsReturnedError if multiple records are found
        """
        # filter if needed
        qs = self if filter_by is None else self.select(filter_by=filter_by)

        # check one and only one
        if len(qs) == 0:
            raise RecordDoesNotExistError("Queryset set contains no value.")
        if len(qs) > 1:
            raise MultipleRecordsReturnedError("Queryset contains more than one value.")

        # return record
        return qs[0]
def one(self, filter_by=None):
        """
        Parameters
        ----------
        filter_by: callable, default None
            Callable must take one argument (a record of table), and return True to keep record, or False to skip it.
            Example : .one(lambda x: x.name == "my_name").
            If None, records are not filtered.

        Returns
        -------
        Record instance if one and only one record is found. Else raises.

        Raises
        ------
        RecordDoesNotExistError if no record is found
        MultipleRecordsReturnedError if multiple records are found
        """
        # filter if needed
        qs = self if filter_by is None else self.select(filter_by=filter_by)

        # check one and only one
        if len(qs) == 0:
            raise RecordDoesNotExistError("Queryset set contains no value.")
        if len(qs) > 1:
            raise MultipleRecordsReturnedError("Queryset contains more than one value.")

        # return record
        return qs[0]
Parameters
        ----------
        filter_by: callable, default None
            Callable must take one argument (a record of table), and return True to keep record, or False to skip it.
            Example : .one(lambda x: x.name == "my_name").
            If None, records are not filtered.

        Returns
        -------
        Record instance if one and only one record is found. Else raises.

        Raises
        ------
        RecordDoesNotExistError if no record is found
        MultipleRecordsReturnedError if multiple records are found