[block] Block Header for easier access to time etc.

bitshares/block.py

@@ -39,3 +39,19 @@ class Block(BlockchainObject):
         """ Return a datatime instance for the timestamp of this block
         """
         return parse_time(self['timestamp'])
+
+
+class BlockHeader(BlockchainObject):
+    def refresh(self):
+        """ Even though blocks never change, you freshly obtain its contents
+            from an API with this method
+        """
+        block = self.bitshares.rpc.get_block_header(self.identifier)
+        if not block:
+            raise BlockDoesNotExistsException
+        super(BlockHeader, self).__init__(block)
+
+    def time(self):
+        """ Return a datatime instance for the timestamp of this block
+        """
+        return parse_time(self['timestamp'])