let pythonTwistedOverride = python-self: python-super: { twisted = python-super.callPackage ../pkgs/twisted.nix { inherit (python-super) twisted; }; }; in self: super: { privatestorage = self.python27.buildEnv.override { extraLibs = [ self.python27Packages.tahoe-lafs self.python27Packages.zkapauthorizer ]; # Twisted's dropin.cache always collides between different # plugin-providing packages. # ignoreCollisions = true; }; python27 = super.python27.override (old: { packageOverrides = super.lib.composeExtensions old.packageOverrides pythonTwistedOverride; }); }