def dissolve_admin_units(gdf):
    """
    Returns input gdf with dissolved geometries based on identical values in 'adm_id'

    Parameters:
    -----------
    gdf :   (gpd.GeoDataFrame)
        Geodataframe to dissolve with field of 'adm_id'

    Returns:
    ---------
    gdf :   (gpd.GeoDataFrame)
        Geodataframe with dissolved geometries based on idential values in 'adm_id'
    """	
    gdf = gdf.reset_index()
    gdf['adm_id'] = gdf['labels']
    gdf = gdf.dissolve(by='adm_id')
    return gdf