Use OrderedDict to represent Params instead of plain dict.

Preserves ordering from the XML which may be desirable.

setup.py

@@ -4,7 +4,7 @@
 
 setup(
     name="voevent-parse",
-    version="0.9.1",
+    version="0.9.2",
     packages=['voeventparse', 'voeventparse.tests', 'voeventparse.tests.resources'],
     package_data={'voeventparse':['tests/resources/*.xml']},
     description="Convenience routines for parsing and manipulation of "

voeventparse/convenience.py

@@ -3,6 +3,7 @@
 from __future__ import absolute_import
 import iso8601
 import lxml
+from collections import OrderedDict
 from voeventparse.misc import (Param, Group, Reference, Inference, Position2D,
                                Citation)
 
@@ -105,11 +106,11 @@ def pull_params(voevent):
             what_dict[None]['ParamName']['value']
 
     """
-    result = {}
+    result = OrderedDict()
     w = voevent.What
     if w.countchildren() == 0:
         return result
-    toplevel_params = {}
+    toplevel_params = OrderedDict()
     result[None] = toplevel_params
     if hasattr(voevent.What, 'Param'):
         for p in voevent.What.Param:

voeventparse/tests/test_voeventparse.py

@@ -327,13 +327,17 @@ def test_pull_astro_coords(self):
         self.assertIsInstance(p.ra, float)
 
     def test_pull_params(self):
-        params = vp.pull_params(self.swift_grb_v2_packet)
+        swift_params = vp.pull_params(self.swift_grb_v2_packet)
 
         #General example, check basic functionality
-        self.assertEqual(params[None]['Packet_Type']['value'], '61')
-        self.assertEqual(params['Misc_Flags']['Values_Out_of_Range']['value'],
+        self.assertEqual(swift_params[None]['Packet_Type']['value'], '61')
+        self.assertEqual(swift_params['Misc_Flags']['Values_Out_of_Range']['value'],
                          'false')
 
+        #Check ordering is preserved
+        self.assertEqual(list(swift_params[None].keys())[:3],
+                         ['Packet_Type', 'Pkt_Ser_Num', 'TrigID'])
+
         #Test empty What section
         params = vp.pull_params(self.blank)
         self.assertEqual(params, {})