def field_size(field_label):
    """
    Helper function to determine the size of a binary
    table field

    Parameters
    ----------
    field_label : PVLModule
                  The field label

    Returns
    -------
    int :
        The size of the one entry in bytes
    """
    data_sizes = {
        'Integer' : 4,
        'Double'  : 8,
        'Real'    : 4,
        'Text'    : 1
    }
    return data_sizes[field_label['Type']] * field_label['Size']