Minor Code Changes.

stix2/base.py

@@ -73,8 +73,7 @@ class _STIXBase(collections.Mapping):
         failed_dependency_pairs = []
         for p in list_of_properties:
             for dp in list_of_dependent_properties:
-                if ((not hasattr(self, p) or (hasattr(self, p) and not self.__getattr__(p))) and
-                        hasattr(self, dp) and self.__getattr__(dp)):
+                if not self.get(p) and self.get(dp):
                     failed_dependency_pairs.append((p, dp))
         if failed_dependency_pairs:
             raise DependentPropertiesError(self.__class__, failed_dependency_pairs)
@@ -125,10 +124,8 @@ class _STIXBase(collections.Mapping):
 
     # Handle attribute access just like key access
     def __getattr__(self, name):
-        try:
-            # Return attribute value.
+        if name in self:
             return self.__getitem__(name)
-        except KeyError:
         raise AttributeError("'%s' object has no attribute '%s'" %
                              (self.__class__.__name__, name))
 
@@ -160,7 +157,7 @@ class _STIXBase(collections.Mapping):
 
     def new_version(self, **kwargs):
         unchangable_properties = []
-        if hasattr(self, 'revoked') and self.revoked:
+        if self.get("revoked"):
             raise RevokeError("new_version")
         new_obj_inner = copy.deepcopy(self._inner)
         properties_to_change = kwargs.keys()
@@ -180,7 +177,7 @@ class _STIXBase(collections.Mapping):
         return cls(**new_obj_inner)
 
     def revoke(self):
-        if hasattr(self, 'revoked') and self.revoked:
+        if self.get("revoked"):
             raise RevokeError("revoke")
         return self.new_version(revoked=True)
 

stix2/observables.py

@@ -6,7 +6,7 @@ and do not have a '_type' attribute.
 """
 
 from .base import _Extension, _Observable, _STIXBase
-from .exceptions import AtLeastOnePropertyError
+from .exceptions import AtLeastOnePropertyError, DependentPropertiesError
 from .properties import (BinaryProperty, BooleanProperty, DictionaryProperty,
                          EmbeddedObjectProperty, EnumProperty,
                          ExtensionsProperty, FloatProperty, HashesProperty,
@@ -110,7 +110,11 @@ class EmailMessage(_Observable):
     def _check_object_constraints(self):
         super(EmailMessage, self)._check_object_constraints()
         self._check_properties_dependency(["is_multipart"], ["body_multipart"])
-        # self._dependency(["is_multipart"], ["body"], [False])
+        if self.get("is_multipart") is False and self.get("body"):
+            raise DependentPropertiesError(
+                self.__class__,
+                (self.get("is_multipart"), self.get("body"))
+            )
 
 
 class ArchiveExt(_Extension):
@@ -443,13 +447,13 @@ class Process(_Observable):
         super(Process, self)._check_object_constraints()
         try:
             self._check_at_least_one_property()
-            if hasattr(self, 'extensions') and "windows-process-ext" in self.extensions:
+            if "windows-process-ext" in self.get("extensions", []):
                 self.extensions["windows-process-ext"]._check_at_least_one_property()
         except AtLeastOnePropertyError as enclosing_exc:
             if not hasattr(self, 'extensions'):
                 raise enclosing_exc
             else:
-                if "windows-process-ext" in self.extensions:
+                if "windows-process-ext" in self.get("extensions", []):
                     self.extensions["windows-process-ext"]._check_at_least_one_property()