def eye(cls, length: int) -> Self:
        """Creates a dense pauli string containing only identity gates.

        Args:
            length: The length of the dense pauli string.
        """
        concrete_cls = cast(Callable, DensePauliString if cls is BaseDensePauliString else cls)
        return concrete_cls(pauli_mask=np.zeros(length, dtype=np.uint8))
Creates a dense pauli string containing only identity gates.

        Args:
            length: The length of the dense pauli string.
        
cirq-core/cirq/ops/dense_pauli_string.py