Add .travis.yml to run mypy. (#192)

* Add typing to modules/tfl.py.

* Add .travis.yml to run mypy.

.travis.yml

@@ -0,0 +1,12 @@
+language: python
+cache: pip
+python:
+  - "3.6"
+  - "3.7"
+  - "3.8"
+  - "3.8-dev"
+  - "nightly"
+install:
+  - pip3 install mypy -r requirements.txt
+script:
+  - mypy --ignore-missing-imports src ./bitbotd modules/

modules/tfl.py

@@ -1,6 +1,6 @@
 #--depends-on commands
 
-import collections, datetime, re
+import collections, datetime, re, typing
 from src import ModuleManager, utils
 
 URL_BUS = "https://api.tfl.gov.uk/StopPoint/%s/Arrivals"
@@ -22,7 +22,7 @@ PLATFORM_TYPES = ["Northbound", "Southbound", "Eastbound", "Westbound", "Inner R
 
 class Module(ModuleManager.BaseModule):
     _name = "TFL"
-    result_map = {}
+    result_map: typing.Dict[int, typing.Dict[int, typing.Dict[str, typing.Any]]] = {}
 
     def vehicle_span(self, arrival_time, human=True):
         vehicle_due_iso8601 = arrival_time