minor edits to examples/py/async.py
minor edits to examples/py/async.py

tritoanst/ccxt,thijstriemstra/ccxt,thijstriemstra/ccxt,ccxt/ccxt,aiueogawa/ccxt,ccxt/ccxt,aiueogawa/ccxt,ccxt/ccxt,tritoanst/ccxt,tritoanst/ccxt,ccxt/ccxt,thijstriemstra/ccxt,ccxt/ccxt,thijstriemstra/ccxt,aiueogawa/ccxt,aiueogawa/ccxt,tritoanst/ccxt