CODE EXAMPLE FOR PYTHON

raise keyerror(key) from none os.environ

#raise keyerror(key) from none os.environ
# Move over while creating .env file first time you will get this error.To resolve this error.
Open your .env file it's contains key value pairs in it.
if it contains space after Key then remove that space from it.
Ex:
DATABASE_URL =postgres://127.0.0.1:5432/my_db_name
    changed to(hear removed space after DATABASE_URL)
DATABASE_URL=postgres://127.0.0.1:5432/my_db_name
    More over it's accures for this reason. No your problem will solved.