def parse_serialized(cls, key_str: str) -> MeasurementKey:
        """Parses the serialized string representation of `Measurementkey` into a `MeasurementKey`.

        This is the only way to construct a `MeasurementKey` from a nested string representation
        (where the path is joined to the key name by the `MEASUREMENT_KEY_SEPARATOR`)"""
        components = key_str.split(MEASUREMENT_KEY_SEPARATOR)
        return MeasurementKey(name=components[-1], path=tuple(components[:-1]))
Parses the serialized string representation of `Measurementkey` into a `MeasurementKey`.

        This is the only way to construct a `MeasurementKey` from a nested string representation
        (where the path is joined to the key name by the `MEASUREMENT_KEY_SEPARATOR`)
cirq-core/cirq/value/measurement_key.py