Correct issues highlighted by Flake8

Flake8 validates code style against PEP 8 in order to encourage the
writing of idiomatic Python. For reference, I am currently ignoring
errors about line length (E501) because I feel it makes code harder
to read.

This is the invocation I am using:

    $ flake8 --ignore E501 dspace_statistics_api

dspace_statistics_api/app.py

@@ -4,6 +4,7 @@ import falcon
 db = database_connection()
 db.set_session(readonly=True)
 
+
 class RootResource:
     def on_get(self, req, resp):
         resp.status = falcon.HTTP_200
@@ -11,6 +12,7 @@ class RootResource:
         with open('dspace_statistics_api/docs/index.html', 'r') as f:
             resp.body = f.read()
 
+
 class AllItemsResource:
     def on_get(self, req, resp):
         """Handles GET requests"""
@@ -46,6 +48,7 @@ class AllItemsResource:
 
         resp.media = message
 
+
 class ItemResource:
     def on_get(self, req, resp, item_id):
         """Handles GET requests"""
@@ -70,6 +73,7 @@ class ItemResource:
 
         cursor.close()
 
+
 api = application = falcon.API()
 api.add_route('/', RootResource())
 api.add_route('/items', AllItemsResource())

dspace_statistics_api/database.py

@@ -3,7 +3,9 @@ from .config import DATABASE_USER
 from .config import DATABASE_PASS
 from .config import DATABASE_HOST
 from .config import DATABASE_PORT
-import psycopg2, psycopg2.extras
+import psycopg2
+import psycopg2.extras
+
 
 def database_connection():
     connection = psycopg2.connect("dbname={} user={} password={} host={} port={}".format(DATABASE_NAME, DATABASE_USER, DATABASE_PASS, DATABASE_HOST, DATABASE_PORT), cursor_factory=psycopg2.extras.DictCursor)

dspace_statistics_api/indexer.py

@@ -34,6 +34,7 @@ import json
 import psycopg2.extras
 from .solr import solr_connection
 
+
 def index_views():
     # get total number of distinct facets for items with a minimum of 1 view,
     # otherwise Solr returns all kinds of weird ids that are actually not in
@@ -98,6 +99,7 @@ def index_views():
 
     cursor.close()
 
+
 def index_downloads():
     # get the total number of distinct facets for items with at least 1 download
     res = solr.query('statistics', {
@@ -157,6 +159,7 @@ def index_downloads():
 
     cursor.close()
 
+
 db = database_connection()
 solr = solr_connection()
 

dspace_statistics_api/solr.py

@@ -1,6 +1,7 @@
 from .config import SOLR_SERVER
 from SolrClient import SolrClient
 
+
 def solr_connection():
     connection = SolrClient(SOLR_SERVER)