morphlib/morphloader.py: Add a check to load_from_string()

1 files changed, 5 insertions, 1 deletions

diff --git a/morphlib/morphloader.py b/morphlib/morphloader.py
index d257dced..e0f0952b 100644
--- a/morphlib/morphloader.py
+++ b/morphlib/morphloader.py
@@ -398,13 +398,17 @@ class MorphologyLoader(object):
 
         return morphlib.morphology.Morphology(obj)
 
-    def load_from_string(self, string, filename='string'):
+    def load_from_string(self, string,
+                         filename='string'):  # pragma: no cover
         '''Load a morphology from a string.
 
         Return the Morphology object.
 
         '''
 
+        if string is None:
+            return None
+
         m = self.parse_morphology_text(string, filename)
         m.filename = filename
         self.validate(m)