from fit2gpx import Converter
from os import listdir
from os.path import isfile, join

mypath='/container/directory'

onlyfiles = [f for f in listdir(mypath) if isfile(join(mypath, f))]

conv = Converter()

for f in onlyfiles:
    if "activity_uncompleted" in f:
        print("   Ignore" + f)
    elif f.endswith(".fit"):
        print(mypath+'/'+f)
        gpx = conv.fit_to_gpx(f_in=mypath+'/'+f, f_out=mypath+'/'+f+'test.gpx')