Updated find geckodriver mechanism

bot_z/bot_z.py

@@ -9,15 +9,25 @@ from datetime import datetime, timedelta
 import logging
 import os
 import pkg_resources
+import shutil
+import sys
 import time
 import typing as T
 from urllib.parse import urlparse
 
-os.environ['PATH'] = os.environ['PATH'] + \
-    ':' + pkg_resources.resource_filename(__name__, 'bin')
+geckoexe = shutil.which('geckodriver')
+if geckoexe is None:
+    local_path = pkg_resources.resource_filename(__name__, 'bin')
+    try:
+        os.stat(os.path.join(local_path, 'geckodriver'))
+        os.environ['PATH'] = os.environ['PATH'] + \
+            ':' + local_path
+    except FileNotFoundError:
+        print("Missing geckodriver executable in path", file=sys.stderr)
+        raise
 
-from selenium import webdriver as wd
-from selenium.common.exceptions import WebDriverException, NoSuchElementException
+from selenium import webdriver as wd  # noqa
+from selenium.common.exceptions import WebDriverException, NoSuchElementException  # noqa
 
 
 logging.basicConfig(