def __init__(self, depol_prob: float, prepend: bool = False):
        """A depolarizing noise model

        Args:
            depol_prob: Depolarizing probability.
            prepend: If True, put noise before affected gates. Default: False.
        """
        value.validate_probability(depol_prob, 'depol prob')
        self.qubit_noise_gate = ops.DepolarizingChannel(depol_prob)
        self._prepend = prepend
A depolarizing noise model

        Args:
            depol_prob: Depolarizing probability.
            prepend: If True, put noise before affected gates. Default: False.
        
cirq-core/cirq/contrib/noise_models/noise_models.py