Defining coordinate system for every GeoDataFrame (shapefile) in list

I am looking to set a coordinate system for every GeoDataFrame in a list of them. So I need this:

gdfs[0].crs = "EPSG:6668"
gdfs[1].crs = "EPSG:6668"

And so on but iteratively. I tried:

([gdfs.crs = "EPSG:6668"] for file in gdfs)

And:

for file in gdfs:
    gdfs.crs = "EPSG:6668"

But not working, any solution?

for gdf in gdfs:
    gdf.crs = "EPSG:6668"

for i in range(len(gdfs)):
   gdfs[i].crs = "EPSG:6668"