from typing import List


def parse_gammas(
    out_channels: List[int], gammas: List[float]
):
    """
    Parse gammas parameter.

    Parameters
    ----------
    out_channels
        Channel indexes expected in the output
    gammas
        List of gammas. List length is 0, 1, or len(out_channels)
    Returns
    -------
    gammas:
        List of gammas. List length is the number of channels in the output.
    """
    if len(gammas) == 0:
        return [1] * len(out_channels)
    elif len(gammas) == 1:
        return gammas * len(out_channels)
    else:
        return gammas