Add helper methods for initialisation from json data

Added helper methods to initialise model member variables.  Now
the models' constructors will not throw exception if a value is
missing, but instead just initialise the variable to None.

Change-Id: I7473ec9bb471f95ea0142067af4750c7e26a0339

1 files changed, 10 insertions, 4 deletions

diff --git a/pygerrit/__init__.py b/pygerrit/__init__.py
index cb77bdc..100380b 100644
--- a/pygerrit/__init__.py
+++ b/pygerrit/__init__.py
@@ -1,7 +1,13 @@
 """ Module to interface with Gerrit. """
 
 
-from pygerrit.error import *
-from pygerrit.events import *
-from pygerrit.models import *
-from pygerrit.stream import *
+def from_json(json_data, key):
+    """ Helper method to extract values from JSON data.
+
+    Return the value of `key` from `json_data`, or None if `json_data`
+    does not contain `key`.
+
+    """
+    if key in json_data:
+        return json_data[key]
+    return None