def _check_chn_type(channels, available_channels):
    """
    Function used for checking weather the elements in "channels" input are coincident with the
    available channels.

    ----------
    Parameters
    ----------
    channels : list [[mac_address_1_channel_1 <int>, mac_address_1_channel_2 <int>...],
                    [mac_address_2_channel_1 <int>...]...]
        From which channels will the data be loaded.

    available_channels : dict
        Dictionary with the list of all the available channels per device.

    Returns
    -------
    out : list
        It is returned a list of the selected channels in a standardized format.

    """

    # ------------------------ Definition of constants and variables -------------------------------
    chn_list_standardized = []

    # %%%%%%%%%%%%%%%%%%%%%%%%%%% Fill of "chn_list_standardized" %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    devices = list(available_channels.keys())
    for dev_nbr, device in enumerate(devices):
        if channels is not None:
            sub_unit = channels[dev_nbr]
            for channel in sub_unit:  # Each sublist must be composed by integers.
                if channel in available_channels[devices[dev_nbr]]:
                    continue
                else:
                    raise RuntimeError("At least one of the specified channels is not available in "
                                       "the acquisition file.")
            chn_list_standardized.append(sub_unit)

        else:  # By omission all the channels were selected.
            chn_list_standardized.append(available_channels[device])

    return chn_list_standardized
Function used for checking weather the elements in "channels" input are coincident with the
    available channels.

    ----------
    Parameters
    ----------
    channels : list [[mac_address_1_channel_1 <int>, mac_address_1_channel_2 <int>...],
                    [mac_address_2_channel_1 <int>...]...]
        From which channels will the data be loaded.

    available_channels : dict
        Dictionary with the list of all the available channels per device.

    Returns
    -------
    out : list
        It is returned a list of the selected channels in a standardized format.