def get_vgroups(variables):
    """ Returns a list of unique vgroup found in the given variables
    object.

    Parameters
    ----------
    variables : list
        Decipher variables object, which is a list of dictionaries

    Returns
    -------
    vgroups : list
        List of unique vgroups found in variables
    """


    vgroups = []  
    for var in variables:
        if not var['vgroup'] in vgroups:
            vgroups.append(var['vgroup'])
    
    return vgroups