def factor(
        self, axes: Sequence[int], *, validate=True, atol=1e-07
    ) -> tuple[_BufferedDensityMatrix, _BufferedDensityMatrix]:
        """Factors out the desired axes.

        Args:
            axes: The axes to factor out. Only the left axes should be provided. For example, to
                extract [C,A] from density matrix of shape [A,B,C,D,A,B,C,D], `axes` should be
                [2,0], and the return value will be two density matrices ([C,A,C,A], [B,D,B,D]).
            validate: Perform a validation that the density matrix factors cleanly.
            atol: The absolute tolerance for the validation.
            Returns:
                A tuple with the `(extracted, remainder)` density matrices, where `extracted` means
                the sub-matrix which corresponds to the axes requested, and with the axes in the
                requested order, and where `remainder` means the sub-matrix on the remaining axes,
                in the same order as the original density matrix.
        """
        extracted_tensor, remainder_tensor = transformations.factor_density_matrix(
            self._density_matrix, axes, validate=validate, atol=atol
        )
        extracted = _BufferedDensityMatrix(density_matrix=extracted_tensor)
        remainder = _BufferedDensityMatrix(density_matrix=remainder_tensor)
        return extracted, remainder
Factors out the desired axes.

        Args:
            axes: The axes to factor out. Only the left axes should be provided. For example, to
                extract [C,A] from density matrix of shape [A,B,C,D,A,B,C,D], `axes` should be
                [2,0], and the return value will be two density matrices ([C,A,C,A], [B,D,B,D]).
            validate: Perform a validation that the density matrix factors cleanly.
            atol: The absolute tolerance for the validation.
            Returns:
                A tuple with the `(extracted, remainder)` density matrices, where `extracted` means
                the sub-matrix which corresponds to the axes requested, and with the axes in the
                requested order, and where `remainder` means the sub-matrix on the remaining axes,
                in the same order as the original density matrix.
        
cirq-core/cirq/sim/density_matrix_simulation_state.py