def synthesize(self, duration, freqs_in_hz=[440.]):
        """
        Synthesize one or more sine waves

        Args:
            duration (numpy.timdelta64): The duration of the sound to be
                synthesized
            freqs_in_hz (list of float): Numbers representing the frequencies
                in hz that should be synthesized
        """
        freqs = np.array(freqs_in_hz)
        scaling = 1 / len(freqs)
        sr = int(self.samplerate)
        cps = freqs / sr
        ts = (duration / Seconds(1)) * sr
        ranges = np.array([np.arange(0, ts * c, c) for c in cps])
        raw = (np.sin(ranges * (2 * np.pi)) * scaling).sum(axis=0)
        return AudioSamples(raw, self.samplerate)
Synthesize one or more sine waves

        Args:
            duration (numpy.timdelta64): The duration of the sound to be
                synthesized
            freqs_in_hz (list of float): Numbers representing the frequencies
                in hz that should be synthesized