diff --git a/src/saml2/assertion.py b/src/saml2/assertion.py
index 35a11dd..adfeecd 100644
--- a/src/saml2/assertion.py
+++ b/src/saml2/assertion.py
@@ -273,13 +273,8 @@ def post_entity_categories(maps, **kwargs):
         required = []
 
     if kwargs["mds"]:
-        try:
+        if "sp_entity_id" in kwargs:
             ecs = kwargs["mds"].entity_categories(kwargs["sp_entity_id"])
-        except KeyError:
-            for ec_map in maps:
-                for attr in ec_map[""]:
-                    restrictions[attr] = None
-        else:
             for ec_map in maps:
                 for key, (atlist, only_required) in ec_map.items():
                     if key == "":  # always released
@@ -305,6 +300,10 @@ def post_entity_categories(maps, **kwargs):
 
                     for attr in attrs:
                         restrictions[attr] = None
+        else:
+            for ec_map in maps:
+                for attr in ec_map[""]:
+                    restrictions[attr] = None
 
     return restrictions
 
diff --git a/src/saml2/discovery.py b/src/saml2/discovery.py
index cef8ff3..8031b41 100644
--- a/src/saml2/discovery.py
+++ b/src/saml2/discovery.py
@@ -1,4 +1,7 @@
-from six.moves.urllib.parse import urlencode, parse_qs, urlparse
+from future.backports.urllib.parse import parse_qs
+from future.backports.urllib.parse import urlencode
+from future.backports.urllib.parse import urlparse
+
 from saml2.entity import Entity
 from saml2.response import VerificationError
 
@@ -9,7 +12,8 @@ IDPDISC_POLICY = "urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol:si
 
 class DiscoveryServer(Entity):
     def __init__(self, config=None, config_file=""):
-        Entity.__init__(self, "disco", config, config_file)
+        if config or config_file:
+            Entity.__init__(self, "disco", config, config_file)
 
     def parse_discovery_service_request(self, url="", query=""):
         if url:
@@ -22,7 +26,8 @@ class DiscoveryServer(Entity):
 
         # verify
 
-        for key in ["isPassive", "return", "returnIDParam", "policy"]:
+        for key in ["isPassive", "return", "returnIDParam", "policy",
+                    'entityID']:
             try:
                 assert len(dsr[key]) == 1
                 dsr[key] = dsr[key][0]
diff --git a/src/saml2/mdstore.py b/src/saml2/mdstore.py
index 28d6061..621752b 100644
--- a/src/saml2/mdstore.py
+++ b/src/saml2/mdstore.py
@@ -269,7 +269,7 @@ class MetaData(object):
         """
         Return any entity that matches the specification
 
-        :param typ:
+        :param typ: Type of entity
         :param service:
         :param binding:
         :return:
@@ -282,6 +282,37 @@ class MetaData(object):
 
         return res
 
+    def any2(self, typ, service, binding=None):
+        """
+
+        :param type:
+        :param service:
+        :param binding:
+        :return:
+        """
+        res = {}
+        for entid, item in self.items():
+            hit = False
+            try:
+                descr = item['{}sso_descriptor'.format(typ)]
+            except KeyError:
+                continue
+            else:
+                for desc in descr:
+                    try:
+                        srvs = desc[service]
+                    except KeyError:
+                        continue
+                    else:
+                        for srv in srvs:
+                            if srv['binding'] == binding:
+                                res[entid] = item
+                                hit = True
+                                break
+                    if hit:
+                        break
+        return res
+
     def bindings(self, entity_id, typ, service):
         """
         Get me all the bindings that are registered for a service entity
@@ -305,7 +336,7 @@ class MetaData(object):
         raise NotImplementedError
 
     def dumps(self):
-        return json.dumps(self.items(), indent=2)
+        return json.dumps(list(self.items()), indent=2)
 
     def with_descriptor(self, descriptor):
         '''
diff --git a/tests/test_37_entity_categories.py b/tests/test_37_entity_categories.py
index 5161df2..625caaa 100644
--- a/tests/test_37_entity_categories.py
+++ b/tests/test_37_entity_categories.py
@@ -1,19 +1,11 @@
 from contextlib import closing
-from saml2 import saml, sigver
-from saml2 import md
+from saml2 import sigver
 from saml2 import config
 from saml2.assertion import Policy
 from saml2.attribute_converter import ac_factory
-from saml2.extension import mdui
-from saml2.extension import idpdisc
-from saml2.extension import dri
-from saml2.extension import mdattr
-from saml2.extension import ui
 from pathutils import full_path
 from saml2.mdstore import MetadataStore
 from saml2.server import Server
-from saml2 import xmldsig
-from saml2 import xmlenc
 
 
 ATTRCONV = ac_factory(full_path("attributemaps"))
diff --git a/tools/verify_metadata.py b/tools/verify_metadata.py
index ac211b9..c13b7ac 100755
--- a/tools/verify_metadata.py
+++ b/tools/verify_metadata.py
@@ -2,20 +2,8 @@
 
 import argparse
 
-from saml2 import saml
-from saml2 import md
-from saml2 import xmldsig
-from saml2 import xmlenc
-
 from saml2.attribute_converter import ac_factory
 from saml2.httpbase import HTTPBase
-from saml2.extension import dri
-from saml2.extension import idpdisc
-from saml2.extension import mdattr
-from saml2.extension import mdrpi
-from saml2.extension import mdui
-from saml2.extension import shibmd
-from saml2.extension import ui
 
 from saml2.sigver import _get_xmlsec_cryptobackend
 from saml2.sigver import SecurityContext