Optimize and refactor internal seek functions

pygeoip/const.py

@@ -362,11 +362,16 @@ CITY_EDITION_REV0 = 6
 CITY_EDITION_REV1 = 2
 ORG_EDITION = 5
 ISP_EDITION = 4
-PROXY_EDITION = 8
 ASNUM_EDITION = 9
+# Not yet supported databases
+PROXY_EDITION = 8
 NETSPEED_EDITION = 11
 COUNTRY_EDITION_V6 = 12
 
+# Collection of databases
+CITY_EDITIONS = (CITY_EDITION_REV0, CITY_EDITION_REV1)
+REGION_EDITIONS = (REGION_EDITION_REV0, REGION_EDITION_REV1)
+
 SEGMENT_RECORD_LENGTH = 3
 STANDARD_RECORD_LENGTH = 3
 ORG_RECORD_LENGTH = 4

pygeoip/timezone.py

@@ -699,17 +699,17 @@ _country["ZW"] = "Africa/Harare"
 
 
 def time_zone_by_country_and_region(country_code, region_name=None):
-
     if country_code not in _country:
-        return None
+        return ''
 
     if not region_name or region_name == '00':
         region_name = None
 
     timezones = _country[country_code]
-
     if isinstance(timezones, str):
         return timezones
 
-    if region_name:
-        return timezones.get(region_name)
+    if not region_name:
+        return ''
+
+    return timezones.get(region_name)

tests/test_city.py

@@ -40,7 +40,8 @@ class TestGeoIPCityFunctions(unittest.TestCase):
             'longitude': -0.23339999999998895,
             'country_code3': 'GBR',
             'latitude': 51.283299999999997,
-            'postal_code': None, 'dma_code': 0,
+            'postal_code': '',
+            'dma_code': 0,
             'country_code': 'GB',
             'country_name': 'United Kingdom',
             'time_zone': 'Europe/London'