Apply suggestions from code review

Co-Authored-By: Theo Julienne <theojulienne@github.com>

octodns/manager.py

@@ -283,6 +283,8 @@ class Manager(object):
             self.log.info('sync:   sources=%s -> targets=%s', sources, targets)
 
             try:
+                # rather than using a list comprehension, we break this loop out
+                # so that the `except` block below can reference the `source`
                 collected = []
                 for source in sources:
                     collected.append(self.providers[source])
@@ -408,6 +410,8 @@ class Manager(object):
                                        .format(zone_name))
 
             try:
+                # rather than using a list comprehension, we break this loop out
+                # so that the `except` block below can reference the `source`
                 collected = []
                 for source in sources:
                     collected.append(self.providers[source])

octodns/provider/rackspace.py

@@ -14,7 +14,7 @@ from .base import BaseProvider
 
 
 def _value_keyer(v):
-    return '{}-{}-{}'.format(v.get('type', ''), v['name'], v.get('data', ''))
+    return (v.get('type', ''), v['name'], v.get('data', ''))
 
 
 def add_trailing_dot(s):

octodns/record/__init__.py

@@ -926,7 +926,7 @@ class MxValue(object):
         }
 
     def __hash__(self):
-        return hash('{} {}'.format(self.preference, self.exchange))
+        return hash((self.preference, self.exchange))
 
     def __eq__(self, other):
         return ((self.preference, self.exchange) ==