refac: Docs and modern python (remove OrderedDict usage)

Author: fgmacedo

statemachine/callbacks.py

@@ -84,7 +84,7 @@ def __str__(self):
         return ", ".join(str(c) for c in self)
 
     def setup(self, resolver):
-        """Validate configuracions"""
+        """Validate configurations"""
         self._resolver = resolver
         self.items = [
             callback for callback in self.items if callback.setup(self._resolver)

statemachine/statemachine.py

@@ -141,7 +141,6 @@ def current_state_value(self, value):
 
     @property
     def current_state(self):
-        # type: () -> Optional[State]
         return self.states_map.get(self.current_state_value, None)
 
     @current_state.setter

statemachine/transition_list.py

@@ -1,5 +1,3 @@
-from collections import OrderedDict
-
 from .utils import ensure_iterable
 
 
@@ -67,10 +65,9 @@ def add_event(self, event):
 
     @property
     def unique_events(self):
-        # Compat Python2.7: Using OrderedDict to get a unique ordered list
-        tmp_list = OrderedDict()
+        tmp_ordered_unique_events_as_keys_on_dict = {}
         for transition in self.transitions:
             for event in transition.events:
-                tmp_list[event] = True
+                tmp_ordered_unique_events_as_keys_on_dict[event] = True
 
-        return list(tmp_list.keys())
+        return list(tmp_ordered_unique_events_as_keys_on_dict.keys())