def is_edges_simplified(edges_gdf):
    """
    The function checks the presence of possible duplicate geometries in the edges_gdf GeoDataFrame.
     
    Parameters
    ----------
    edges_gdf: LineString GeoDataFrame
        street segments
   
    Returns
    -------
    simplified: boolean
        whether the edges of the network are simplified or not
    """
    
    simplified = True 
    
    edges_gdf['code'] = None
    edges_gdf['code'][edges_gdf['v'] >= edges_gdf['u']] = edges_gdf.u.astype(str)+"-"+edges_gdf.v.astype(str)
    edges_gdf['code'][edges_gdf['v'] < edges_gdf['u']] = edges_gdf.v.astype(str)+"-"+edges_gdf.u.astype(str)
    dd = dict(edges_gdf['code'].value_counts())
    dd = {k: v for k, v in dd.items() if v > 1}
    
    if len(dd) > 0: 
        simplified = False
    
    return simplified