update windows build to Python 3.7

Lib/lib2to3/fixes/fix_funcattrs.py

@@ -0,0 +1,21 @@
+"""Fix function attribute names (f.func_x -> f.__x__)."""
+# Author: Collin Winter
+
+# Local imports
+from .. import fixer_base
+from ..fixer_util import Name
+
+
+class FixFuncattrs(fixer_base.BaseFix):
+    BM_compatible = True
+
+    PATTERN = """
+    power< any+ trailer< '.' attr=('func_closure' | 'func_doc' | 'func_globals'
+                                  | 'func_name' | 'func_defaults' | 'func_code'
+                                  | 'func_dict') > any* >
+    """
+
+    def transform(self, node, results):
+        attr = results["attr"][0]
+        attr.replace(Name(("__%s__" % attr.value[5:]),
+                          prefix=attr.prefix))