python 3.7 compatibility and secret handling

Payload is no longer appended using a python 3.9 feature.
The last refresh time is no longer stored as it was not used.

social_media.py

@@ -1,5 +1,10 @@
 import json, time, requests, re, os
 
+secrets = {
+    "user_id": os.getenv("USER_ID"),
+    "access_token": os.getenv("ACCESS_TOKEN")
+}
+
 def read_data_from_file(filename):
     with open(filename, "r") as file:
         return json.loads(file.read())
@@ -8,21 +13,12 @@ def write_data_to_file(filename, data):
     with open(filename, "w") as file:
         file.write(json.dumps(data, indent=4))
 
-secrets = {
-    "user_id": os.getenv("USER_ID"),
-    "access_token": os.getenv("ACCESS_TOKEN")
-}
-if "last_refresh" in os.environ:
-    secrets["last_refresh"] = os.gerenv("LAST_REFRESH")
-else:
-    secrets["last_refresh"] = 0
-
 def call(url, payload):
     """ Calls the instagram Basic Display API with the given url and payload.
     Returns the response body as a dict.
     Raises HTTPError if the HTTP response code is 4XX or 5XX. """
     # append access token to payload
-    payload |= {"access_token": secrets["access_token"]}
+    payload["access_token"] = secrets["access_token"]
     response = requests.get("https://graph.instagram.com" + url, params=payload, timeout=1)
     response.raise_for_status()
     return response.json()
@@ -34,9 +30,7 @@ def refresh_instagram_access_token():
     response_body = call("/refresh_access_token", {"grant_type": "ig_refresh_token"})
     expiration_date = time.time() + response_body["expires_in"]
     expiration_date = time.strftime("%Y.%m.%d %H:%M", time.gmtime(expiration_date))
-    secrets["last_refresh"] = time.time()
     print(f"Instagram access token refreshed. Expires on {expiration_date}")
-    return secrets
 
 def format_media(media):
     """ Writes the media returned by the IG API in the desired format. """
@@ -60,7 +54,6 @@ def fetch_instagram_media():
     return format_media(response_body["data"])
 
 if __name__ == "__main__":
-    secrets = refresh_instagram_access_token()
-    os.environ["LAST_REFRESH"] = str(secrets["last_refresh"])
+    refresh_instagram_access_token()
     media = fetch_instagram_media()
     write_data_to_file("instagram_media.json", media)