fix unit test for wallet

beem/blockchainobject.py

@@ -18,11 +18,6 @@ class ObjectCache(dict):
         super(ObjectCache, self).__init__(initial_data)
         self.default_expiration = default_expiration
 
-    def clear(self):
-        """ Clears the whole cache
-        """
-        dict.__init__(self, dict())
-
     def __setitem__(self, key, value):
         if key in self:
             del self[key]
@@ -127,8 +122,7 @@ class BlockchainObject(dict):
 
     @staticmethod
     def clear_cache():
-        if BlockchainObject._cache:
-            BlockchainObject._cache.clear()
+        BlockchainObject._cache = ObjectCache()
 
     def test_valid_objectid(self, i):
         if isinstance(i, string_types):

beem/wallet.py

@@ -293,7 +293,8 @@ class Wallet(object):
     def addPrivateKey(self, wif):
         """Add a private key to the wallet database"""
         pub = self._get_pub_from_wif(wif)
-
+        if isinstance(wif, PrivateKey):
+            wif = str(wif)        
         if self.keyStorage:
             # Test if wallet exists
             if not self.created():