def is_channel_valid(channel):
    """
    Verify if a channel string is valid.
    For now a valid channel is a channel in which:
    - It is not None
    - It is not an empty string

    Parameters
    ----------
    channel : str
        The channel value

    Returns
    -------
    valid : bool
        Returns True if the channel is valid, False otherwise.
    """
    return channel is not None and channel != ''
