Add ordereddict dependency for 2.6 support. Import change in utils.py

setup.py

@@ -47,6 +47,7 @@ setup(
     keywords="stix stix2 json cti cyber threat intelligence",
     packages=find_packages(),
     install_requires=[
+        'ordereddict'
         'python-dateutil',
         'pytz',
         'requests',

stix2/common.py

@@ -1,6 +1,9 @@
 """STIX 2 Common Data Types and Properties"""
 
-from collections import OrderedDict
+try:
+    from collections import OrderedDict
+except ImportError:
+    from ordereddict import OrderedDict
 
 from .base import _STIXBase
 from .properties import (BooleanProperty, HashesProperty, IDProperty,

stix2/core.py

@@ -1,6 +1,9 @@
 """STIX 2.0 Objects that are neither SDOs nor SROs"""
 
-from collections import OrderedDict
+try:
+    from collections import OrderedDict
+except ImportError:
+    from ordereddict import OrderedDict
 
 from . import exceptions
 from .base import _STIXBase

stix2/observables.py

@@ -5,7 +5,10 @@ embedded in Email Message objects, inherit from _STIXBase instead of Observable
 and do not have a '_type' attribute.
 """
 
-from collections import OrderedDict
+try:
+    from collections import OrderedDict
+except ImportError:
+    from ordereddict import OrderedDict
 
 from .base import _Extension, _Observable, _STIXBase
 from .exceptions import (AtLeastOnePropertyError, DependentPropertiesError,

stix2/sdo.py

@@ -1,6 +1,9 @@
 """STIX 2.0 Domain Objects"""
 
-from collections import OrderedDict
+try:
+    from collections import OrderedDict
+except ImportError:
+    from ordereddict import OrderedDict
 
 import stix2
 

stix2/sro.py

@@ -1,6 +1,9 @@
 """STIX 2.0 Relationship Objects."""
 
-from collections import OrderedDict
+try:
+    from collections import OrderedDict
+except ImportError:
+    from ordereddict import OrderedDict
 
 from .base import _STIXBase
 from .common import ExternalReference, GranularMarking

stix2/utils.py

@@ -6,8 +6,6 @@ import json
 from dateutil import parser
 import pytz
 
-from .base import _STIXBase
-
 # Sentinel value for properties that should be set to the current time.
 # We can't use the standard 'default' approach, since if there are multiple
 # timestamps in a single object, the timestamps will vary by a few microseconds.
@@ -124,6 +122,7 @@ def find_property_index(obj, properties, tuple_to_find):
     according to the _properties OrderedDict. If its a list look for
     individual objects.
     """
+    from .base import _STIXBase
     try:
         if tuple_to_find[1] in obj._inner.values():
             return properties.index(tuple_to_find[0])