trim usage of "six"

src/foolscap/banana.py

@@ -22,7 +22,7 @@
 
 def int2b128(integer, stream):
     if integer == 0:
-        stream(six.int2byte(0))
+        stream(b'\0')
         return
     assert integer > 0, "can only encode positive integers"
     while integer:

src/foolscap/copyable.py

@@ -340,8 +340,7 @@ class RemoteCopyOldStyle(_RemoteCopyBase):
     # classes do not do metaclass magic
     copytype = None
 
-@six.add_metaclass(RemoteCopyClass)
-class RemoteCopy(_RemoteCopyBase, object):
+class RemoteCopy(_RemoteCopyBase, metaclass=RemoteCopyClass):
     # Set 'copytype' to a unique string that is shared between the
     # sender-side Copyable and the receiver-side RemoteCopy. This RemoteCopy
     # subclass will be auto-registered using the 'copytype' name. Set

src/foolscap/pb.py

@@ -513,7 +513,7 @@ def listenOn(self, what, _test_options={}):
                              "port numbers instead")
             warn(warningString, DeprecationWarning, stacklevel=2)
 
-        if isinstance(what, six.string_types) and re.search(r"^\d+$", what):
+        if isinstance(what, str) and re.search(r"^\d+$", what):
             warn("Tub.listenOn('12345') was deprecated "
                  "in Foolscap 0.12.0; please use qualified endpoint "
                  "descriptions like 'tcp:12345'",

src/foolscap/remoteinterface.py

@@ -1,5 +1,4 @@
 
-import six
 import types
 import inspect
 from zope.interface import interface, providedBy, implementer
@@ -414,5 +413,5 @@ def _makeConstraint(t):
 # See
 # https://github.com/warner/foolscap/pull/76/commits/ff3b9e8c1e4fa13701273a2143ba80b1e58f47cf#r549428977
 # for more background on the use of add_metaclass here.
-class RemoteInterface(six.with_metaclass(RemoteInterfaceClass, interface.Interface)):
+class RemoteInterface(interface.Interface, metaclass=RemoteInterfaceClass):
     pass

src/foolscap/slicer.py

@@ -19,9 +19,8 @@ def __init__(self, name, bases, dict):
         if typ:
             registerAdapter(self, typ, tokens.ISlicer)
 
-@six.add_metaclass(SlicerClass)
 @implementer(tokens.ISlicer)
-class BaseSlicer(object):
+class BaseSlicer(metaclass=SlicerClass):
     slices = None
 
     parent = None
@@ -146,9 +145,8 @@ def __init__(self, name, bases, dict):
         if opentype:
             registerUnslicer(opentype, self, reg)
 
-@six.add_metaclass(UnslicerClass)
 @implementer(tokens.IUnslicer)
-class BaseUnslicer(object):
+class BaseUnslicer(metaclass=UnslicerClass):
     opentype = None
 
     def __init__(self):

src/foolscap/test/test_banana.py

@@ -142,7 +142,7 @@ def untokenize(tokens):
             elif isinstance(t, float):
                 data.append(FLOAT)
                 data.append(struct.pack("!d", t))
-            elif isinstance(t, six.string_types) or isinstance(t, bytes):
+            elif isinstance(t, (str, bytes)):
                 t = six.ensure_binary(t)
                 int2b128(len(t), data.append)
                 data.append(STRING)

src/foolscap/tokens.py

@@ -1,25 +1,24 @@
-import six
 from twisted.python.failure import Failure
 from zope.interface import Attribute, Interface
 
 # delimiter characters.
-LIST     = six.int2byte(0x80) # old
-INT      = six.int2byte(0x81)
-STRING   = six.int2byte(0x82)
-NEG      = six.int2byte(0x83)
-FLOAT    = six.int2byte(0x84)
+LIST     = b'\x80' # old
+INT      = b'\x81'
+STRING   = b'\x82'
+NEG      = b'\x83'
+FLOAT    = b'\x84'
 # "optional" -- these might be refused by a low-level implementation.
-LONGINT  = six.int2byte(0x85) # old
-LONGNEG  = six.int2byte(0x86) # old
+LONGINT  = b'\x85' # old
+LONGNEG  = b'\x86' # old
 # really optional; this is is part of the 'pb' vocabulary
-VOCAB    = six.int2byte(0x87)
+VOCAB    = b'\x87'
 # newbanana tokens
-OPEN     = six.int2byte(0x88)
-CLOSE    = six.int2byte(0x89)
-ABORT    = six.int2byte(0x8A)
-ERROR    = six.int2byte(0x8D)
-PING     = six.int2byte(0x8E)
-PONG     = six.int2byte(0x8F)
+OPEN     = b'\x88'
+CLOSE    = b'\x89'
+ABORT    = b'\x8A'
+ERROR    = b'\x8D'
+PING     = b'\x8E'
+PONG     = b'\x8F'
 
 tokenNames = {
     LIST: "LIST",