Use structural blank lines conformant with PEP 8.

PEP 8 specifies:

* Surround top-level function and class definitions with two blank lines.

* Method definitions inside a class are surrounded by a single blank line.

auth-mastodon.py

@@ -1,6 +1,8 @@
 #!/usr/bin/env python3
+
 import os, sys, logging, struct, psycopg2, bcrypt, random, atexit, time
 
+
 # Database connection details. The credentials here need access to the Mastodon database, which "ejabberd" is unlikely
 # to have on your system by default. You shoud grant SELECT privileges to ejabberd on the "accounts" and "users" tables,
 # to play it safe, or include the Mastodon DB user credentials here (don't).
@@ -38,16 +40,21 @@ except:
     time.sleep(10)
     sys.exit(1)
 
+
 @atexit.register
 def close_db():
     cursor.close()
     database.close()
 
+
 logging.info('auth-mastodon script started, waiting for ejabberd requests')
 
+
 class EjabberdInputError(Exception):
+
     def __init__(self, value):
         self.value = value
+
     def __str__(self):
         return repr(self.value)