def inferred_decay_constant(self) -> Mapping[tuple[cirq.GridQubit, cirq.GridQubit], float]:
        """Return the inferred decay constant for all pairs."""
        return MappingProxyType(
            {
                pair: noise_utils.pauli_error_to_decay_constant(pauli, 2)
                for pair, pauli in self.inferred_pauli_error().items()
            }
        )
Return the inferred decay constant for all pairs.
cirq-core/cirq/experiments/two_qubit_xeb.py