def p_x(self) -> float:
        """The probability that a Pauli X and no other gate occurs."""
        if self._num_qubits != 1:
            raise ValueError('num_qubits should be 1')
        return self._error_probabilities.get('X', 0.0)
The probability that a Pauli X and no other gate occurs.
cirq-core/cirq/ops/common_channels.py