diff --git a/heat/engine/checkeddict.py b/heat/engine/checkeddict.py
index 0147aa58c1..7ecc670a5a 100644
--- a/heat/engine/checkeddict.py
+++ b/heat/engine/checkeddict.py
@@ -15,6 +15,9 @@
 
 import collections
 import re
+import logging
+
+logger = logging.getLogger(__file__)
 
 
 class CheckedDict(collections.MutableMapping):
@@ -49,29 +52,30 @@ class CheckedDict(collections.MutableMapping):
 
         if 'Type' in self.data[key]:
             t = self.data[key]['Type']
-            if self.data[key]['Type'] == 'String':
-                if not isinstance(value, (basestring, unicode)):
-                    raise ValueError('%s: %s Value must be a string' % \
+            if t == 'String':
+                if not isinstance(value, basestring):
+                    raise ValueError('%s: %s Value must be a string' %
                                      (self.name, key))
                 if 'MaxLength' in self.data[key]:
                     if len(value) > int(self.data[key]['MaxLength']):
-                        raise ValueError('%s: %s is too long; MaxLength %s' % \
-                                     (self.name, key,
-                                      self.data[key]['MaxLength']))
+                        raise ValueError('%s: %s is too long; MaxLength %s' %
+                                         (self.name, key,
+                                          self.data[key]['MaxLength']))
                 if 'MinLength' in self.data[key]:
                     if len(value) < int(self.data[key]['MinLength']):
-                        raise ValueError('%s: %s is too short; MinLength %s' %\
-                                     (self.name, key,
-                                      self.data[key]['MinLength']))
+                        raise ValueError('%s: %s is too short; MinLength %s' %
+                                         (self.name, key,
+                                          self.data[key]['MinLength']))
                 if 'AllowedPattern' in self.data[key]:
                     rc = re.match('^%s$' % self.data[key]['AllowedPattern'],
                                   value)
                     if rc == None:
-                        raise ValueError('%s: Pattern %s does not match %s' % \
-                                  (self.name, self.data[key]['AllowedPattern'],
-                                   key))
+                        raise ValueError('%s: Pattern %s does not match %s' %
+                                         (self.name,
+                                          self.data[key]['AllowedPattern'],
+                                          key))
 
-            elif self.data[key]['Type'] in ['Integer', 'Number', 'Float']:
+            elif t in ['Integer', 'Number', 'Float']:
                 # just try convert and see if it will throw a ValueError
                 num = num_converter[t](value)
                 minn = num
@@ -84,20 +88,20 @@ class CheckedDict(collections.MutableMapping):
                     raise ValueError('%s: %s is out of range' % (self.name,
                                                                  key))
 
-            elif self.data[key]['Type'] == 'List':
-                if not isinstance(value, list):
-                    raise ValueError('%s: %s Value must be a list' % \
+            elif t == 'List':
+                if not isinstance(value, (list, tuple)):
+                    raise ValueError('%s: %s Value must be a list' %
                                      (self.name, key))
 
-            elif self.data[key]['Type'] == 'CommaDelimitedList':
+            elif t == 'CommaDelimitedList':
                 sp = value.split(',')
-                if not isinstance(sp, list):
-                    raise ValueError('%s: %s Value must be a list' % \
-                                     (self.name, key))
+
+            else:
+                logger.warn('Unknown value type "%s"' % t)
 
         if 'AllowedValues' in self.data[key]:
             if not value in self.data[key]['AllowedValues']:
-                raise ValueError('%s: %s Value must be one of %s' % \
+                raise ValueError('%s: %s Value must be one of %s' %
                                  (self.name, key,
                                   str(self.data[key]['AllowedValues'])))
 
diff --git a/heat/engine/instance.py b/heat/engine/instance.py
index f0aa58fe8a..10ba59990f 100644
--- a/heat/engine/instance.py
+++ b/heat/engine/instance.py
@@ -96,21 +96,21 @@ class Instance(Resource):
                                               'Implemented': False},
                          'RamDiskId': {'Type': 'String',
                                        'Implemented': False},
-                         'SecurityGroups': {'Type': 'TuplesList',
+                         'SecurityGroups': {'Type': 'List',
                                               'Implemented': False},
-                         'SecurityGroupIds': {'Type': 'CommaDelimitedList',
+                         'SecurityGroupIds': {'Type': 'List',
                                               'Implemented': False},
                          'SourceDestCheck': {'Type': 'Boolean',
                                              'Implemented': False},
                          'SubnetId': {'Type': 'String',
                                        'Implemented': False},
-                         'Tags': {'Type': 'CommaDelimitedList',
+                         'Tags': {'Type': 'List',
                                           'Implemented': False},
                          'Tenancy': {'Type': 'String',
                                      'AllowedValues': ['dedicated', 'default'],
                                      'Implemented': False},
                          'UserData': {'Type': 'String'},
-                         'Volumes': {'Type': 'CommaDelimitedList',
+                         'Volumes': {'Type': 'List',
                                      'Implemented': False}}
 
     def __init__(self, name, json_snippet, stack):
diff --git a/heat/engine/security_group.py b/heat/engine/security_group.py
index 82a463ecdb..344796097b 100644
--- a/heat/engine/security_group.py
+++ b/heat/engine/security_group.py
@@ -29,9 +29,9 @@ class SecurityGroup(Resource):
                                               'Required': True},
                          'VpcId': {'Type': 'String',
                                    'Implemented': False},
-                         'SecurityGroupIngress': {'Type': 'TuplesList',
+                         'SecurityGroupIngress': {'Type': 'List',
                                                   'Implemented': False},
-                         'SecurityGroupEgress': {'Type': 'TuplesList'}}
+                         'SecurityGroupEgress': {'Type': 'List'}}
 
     def __init__(self, name, json_snippet, stack):
         super(SecurityGroup, self).__init__(name, json_snippet, stack)
diff --git a/heat/engine/user.py b/heat/engine/user.py
index 4653a3bf30..e81e27a25c 100644
--- a/heat/engine/user.py
+++ b/heat/engine/user.py
@@ -30,7 +30,7 @@ class User(Resource):
                                     'Implemented': False},
                          'LoginProfile': {'Type': 'String',
                                           'Implemented': False},
-                         'Policies': {'Type': 'TuplesList'}}
+                         'Policies': {'Type': 'List'}}
 
     def __init__(self, name, json_snippet, stack):
         super(User, self).__init__(name, json_snippet, stack)
diff --git a/heat/engine/volume.py b/heat/engine/volume.py
index df49b20edd..0b06c24f5f 100644
--- a/heat/engine/volume.py
+++ b/heat/engine/volume.py
@@ -29,7 +29,7 @@ class Volume(Resource):
                                               'Required': True},
                          'Size': {'Type': 'Number'},
                          'SnapshotId': {'Type': 'String'},
-                         'Tags': {'Type': 'TuplesList'}}
+                         'Tags': {'Type': 'List'}}
 
     def __init__(self, name, json_snippet, stack):
         super(Volume, self).__init__(name, json_snippet, stack)