diff --git a/firmware/nem_mosaics.py b/firmware/nem_mosaics.py
index 096d45394..7b9f25999 100755
--- a/firmware/nem_mosaics.py
+++ b/firmware/nem_mosaics.py
@@ -1,13 +1,13 @@
 #!/usr/bin/env python
-import json, os, sys
+import json
+import os
+import sys
 
-import collections, numbers
+import collections
+import itertools
+import numbers
 
 from google.protobuf import json_format
-from itertools import chain
-
-sys.path.insert(0, os.path.join(os.path.dirname(__file__), "protob"))
-import types_pb2 as types
 
 try:
     basestring
@@ -28,7 +28,7 @@ extern const NEMMosaicDefinition NEM_MOSAIC_DEFINITIONS[NEM_MOSAIC_DEFINITIONS_C
 extern const NEMMosaicDefinition *NEM_MOSAIC_DEFINITION_XEM;
 
 #endif
-""".lstrip()
+""".lstrip()  # noqa: E501
 
 CODE_TEMPLATE = """
 // This file is automatically generated by nem_mosaics.py -- DO NOT EDIT!
@@ -38,7 +38,8 @@ CODE_TEMPLATE = """
 const NEMMosaicDefinition NEM_MOSAIC_DEFINITIONS[NEM_MOSAIC_DEFINITIONS_COUNT] = {code};
 
 const NEMMosaicDefinition *NEM_MOSAIC_DEFINITION_XEM = NEM_MOSAIC_DEFINITIONS;
-""".lstrip()
+""".lstrip()  # noqa: E501
+
 
 def format_primitive(value):
     if isinstance(value, bool):
@@ -54,9 +55,11 @@ def format_primitive(value):
     else:
         raise TypeError
 
+
 def format_struct(struct):
     return "{\n" + "\n".join(
-        "\t.{0} = {1},".format(member, value) for member, value in struct.items()
+        "\t.{0} = {1},".format(member, value)
+        for member, value in struct.items()
     ) + "\n}"
 
 
@@ -64,42 +67,56 @@ def format_field(field, value):
     if field.message_type is not None:
         raise TypeError
     elif field.enum_type:
-        return "{0}_{1}".format(field.enum_type.name, field.enum_type.values_by_number[value].name)
+        type_name = field.enum_type.name
+        enum_name = field.enum_type.values_by_number[value].name
+        return "{0}_{1}".format(type_name, enum_name)
     elif hasattr(value, "_values"):
         return format_primitive(value._values)
     else:
         return format_primitive(value)
 
+
 def field_to_meta(field, value):
     if field.label == field.LABEL_REPEATED:
         return ("{}_count".format(field.name), format_primitive(len(value)))
     else:
         return ("has_{}".format(field.name), format_primitive(True))
 
+
 def message_to_struct(_message, proto):
     message = json_format.ParseDict(_message, proto())
-    return collections.OrderedDict(chain.from_iterable(
+    return collections.OrderedDict(itertools.chain.from_iterable(
         (
             field_to_meta(field, value),
             (field.name, format_field(field, value)),
         ) for field, value in message.ListFields()
     ))
 
+
 def format_message(message, proto):
     return format_struct(message_to_struct(message, proto))
 
+
 def format_messages(messages, proto):
     return "{" + ",\n".join(
         format_message(message, proto) for message in messages
     ) + "}"
 
+
 if __name__ == "__main__":
     os.chdir(os.path.abspath(os.path.dirname(__file__)))
 
+    sys.path.insert(0, "protob")
+    import types_pb2 as types
+
     messages = json.load(open("nem_mosaics.json"))
 
     with open("nem_mosaics.h", "w+") as f:
-        f.write(HEADER_TEMPLATE.format(count=format_primitive(len(messages))))
+        f.write(HEADER_TEMPLATE.format(
+            count=format_primitive(len(messages)))
+        )
 
     with open("nem_mosaics.c", "w+") as f:
-        f.write(CODE_TEMPLATE.format(code=format_messages(messages, types.NEMMosaicDefinition)))
+        f.write(CODE_TEMPLATE.format(
+            code=format_messages(messages, types.NEMMosaicDefinition))
+        )