Delete unused function in gateway.encoding.etf

disco/gateway/encoding/etf.py

@@ -1,20 +1,9 @@
-import six
-
 from websocket import ABNF
-from erlpack import Atom, unpack, pack
+from erlpack import unpack, pack
 
 from disco.gateway.encoding.base import BaseEncoder
 
 
-def make_keys_atom(obj):
-    res = {}
-    for k, v in six.iteritems(obj):
-        if isinstance(v, dict):
-            v = make_keys_atom(v)
-        res[Atom(k)] = v
-    return res
-
-
 class ETFEncoder(BaseEncoder):
     TYPE = 'etf'
     OPCODE = ABNF.OPCODE_BINARY