py_gen: move ID classes into their own modules
diff --git a/py_gen/codegen.py b/py_gen/codegen.py
index 2c4a135..de3fdba 100644
--- a/py_gen/codegen.py
+++ b/py_gen/codegen.py
@@ -40,8 +40,10 @@
 roots = {
     'of_header': 'message',
     'of_action': 'action',
+    'of_action_id': 'action_id',
     'of_oxm': 'oxm',
     'of_instruction': 'instruction',
+    'of_instruction_id': 'instruction_id',
     'of_meter_band': 'meter_band',
 }
 
@@ -74,6 +76,11 @@
                          ofclasses=modules_by_version[version]['action'],
                          version=version)
 
+def generate_action_id(out, name, version):
+    util.render_template(out, 'module.py',
+                         ofclasses=modules_by_version[version]['action_id'],
+                         version=version)
+
 def generate_oxm(out, name, version):
     util.render_template(out, 'module.py',
                          ofclasses=modules_by_version[version]['oxm'],
@@ -94,6 +101,11 @@
                          ofclasses=modules_by_version[version]['instruction'],
                          version=version)
 
+def generate_instruction_id(out, name, version):
+    util.render_template(out, 'module.py',
+                         ofclasses=modules_by_version[version]['instruction_id'],
+                         version=version)
+
 def generate_message(out, name, version):
     util.render_template(out, 'module.py',
                          ofclasses=modules_by_version[version]['message'],