[Python] NotImplemented → NotImplementedError

From the Python documentation:
* NotImplemented: "Special value which can be returned by the 'rich comparison'
  special methods (__eq__(), __lt__(), and friends), to indicate that the
  comparison is not implemented with respect to the other type."
* NotImplementedError: "This exception is derived from RuntimeError. In user
  defined base classes, abstract methods should raise this exception when they
  require derived classes to override the method."

Author: practicalswift

utils/GYBUnicodeDataUtils.py

@@ -15,19 +15,24 @@ class UnicodeProperty(object):
     """Abstract base class for Unicode properties."""
 
     def __init__(self):
-        raise NotImplemented
+        raise NotImplementedError(
+            "UnicodeProperty.__init__ is not implemented.")
 
     def get_default_value(self):
-        raise NotImplemented
+        raise NotImplementedError(
+            "UnicodeProperty.get_default_value is not implemented.")
 
     def get_value(self, cp):
-        raise NotImplemented
+        raise NotImplementedError(
+            "UnicodeProperty.get_value is not implemented.")
 
     def to_numeric_value(self, value):
-        raise NotImplemented
+        raise NotImplementedError(
+            "UnicodeProperty.to_numeric_value is not implemented.")
 
     def get_numeric_value(self, cp):
-        raise NotImplemented
+        raise NotImplementedError(
+            "UnicodeProperty.get_numeric_value is not implemented.")
 
 class GraphemeClusterBreakPropertyTable(UnicodeProperty):
     """Grapheme_Cluster_Break property."""

utils/gyb.py

@@ -561,13 +561,13 @@ class ASTNode(object):
     """Abstract base class for template AST nodes"""
 
     def __init__(self):
-        raise NotImplemented
+        raise NotImplementedError("ASTNode.__init__ is not implemented.")
 
     def execute(self, context):
-        raise NotImplemented
+        raise NotImplementedError("ASTNode.execute is not implemented.")
 
     def __str__(self, indent=''):
-        raise NotImplemented
+        raise NotImplementedError("ASTNode.__str__ is not implemented.")
 
     def format_children(self, indent):
         if not self.children: