Function used for the determination of the available channels in each device.

    ----------
    Parameters
    ----------
    devices : list ["mac_address_1" <str>, "mac_address_2" <str>...]
        List of devices selected by the user.

    header: dict
        Dictionary that contains auxiliary data of the acquisition.

    Returns
    -------
    out : dict
        Returns a dictionary where each device defines a key and the respective value will be a list
        of the available channels for the device.

def _available_channels(devices, header):
    """
    Function used for the determination of the available channels in each device.

    ----------
    Parameters
    ----------
    devices : list ["mac_address_1" <str>, "mac_address_2" <str>...]
        List of devices selected by the user.

    header: dict
        Dictionary that contains auxiliary data of the acquisition.

    Returns
    -------
    out : dict
        Returns a dictionary where each device defines a key and the respective value will be a list
        of the available channels for the device.

    """

    # ------------------------ Definition of constants and variables ------------------------------
    chn_dict = {}

    # %%%%%%%%%%%%%%%%%%%%%% Access to the relevant data in the header %%%%%%%%%%%%%%%%%%%%%%%%%%%%
    for dev in devices:
        chn_dict[dev] = header[dev]["column labels"].keys()

    return chn_dict