def __init__(
        self, stream_sid: str, call_sid: Optional[str] = None, params: Optional[InputParams] = None
    ):
        """Initialize the ExotelFrameSerializer.

        Args:
            stream_sid: The Exotel Media Stream SID.
            call_sid: The associated Exotel Call SID (optional, not used in this implementation).
            params: Configuration parameters.
        """
        self._stream_sid = stream_sid
        self._call_sid = call_sid
        self._params = params or ExotelFrameSerializer.InputParams()

        self._exotel_sample_rate = self._params.exotel_sample_rate
        self._sample_rate = 0  # Pipeline input rate

        self._resampler = create_default_resampler()
Initialize the ExotelFrameSerializer.

        Args:
            stream_sid: The Exotel Media Stream SID.
            call_sid: The associated Exotel Call SID (optional, not used in this implementation).
            params: Configuration parameters.
        
src/pipecat/serializers/exotel.py