from typing import List


def convert_to_frequencies(bins: List[int], sample_rate: float, fft_size: int) -> List[float]:
    """
    Convert the sparse list of bins provided to a list of actual frequencies

    :param bins: A sparse list of bins from an fft, fftshift() already applied
    :param sample_rate: The sample rate in sps
    :param fft_size: The number of bins in the full fft
    :return: A list of frequencies
    """

    # map bins to frequencies, remember our bins are now +- values around zero
    bin_hz = sample_rate / fft_size
    freqs = [(bin_value - fft_size // 2) * bin_hz for bin_value in bins]
    return freqs