tensorflow: Backport upstream as bazel build failing for current

temporary/tf-astunparse.nix

@@ -0,0 +1,17 @@
+{ stdenv, fetchPypi, buildPythonPackage, six }:
+
+buildPythonPackage rec {
+  pname = "astunparse";
+  version =  "1.5.0";
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "1kc9lm2jvfcip3z8snj04dar5a9jh857a704m6lvcv4xclm3rpsm";
+  };
+  propagatedBuildInputs = [ six ];
+  doCheck = false; # no tests
+  meta = with stdenv.lib; {
+    description = "This is a factored out version of unparse found in the Python source distribution";
+    license = licenses.bsd3;
+    maintainers = with maintainers; [ jyp ];
+  };
+}