gistfile1.txt

let
  remove = element: list: builtins.filter (x: x != element) list;
  pbr = pkgs: list: list ++ [ pkgs.pythonPackages.pbr ];
in
  { pkgs, python }:

  # remove Twisted from Automat.propagatedBuildInputs                                                                                                                                                              
  # remove Twisted from incremental.propagatedBuildInputs                                                                                                                                                          
  # remove fixtures from testtools.propagatedBuildInputs                                                                                                                                                           
  # remove pyutil from zbase32 propagatedBuildInputs                                                                                                                                                               

  # remove unittest2 from                                                                                                                                                                                          
  # mock oauthlib testtools                                                                                                                                                                                        

  # replace pbr in propagatedBuildInputs for                                                                                                                                                                       
  # fixtures mock testtools                                                                                                                                                                                        

  self: super: {

    "Automat" = python.overrideDerivation super."Automat" (old: {
      propagatedBuildInputs = remove self."Twisted" old.propagatedBuildInputs;
    });

    "incremental" = python.overrideDerivation super."incremental" (old: {
      propagatedBuildInputs = remove self."Twisted" old.propagatedBuildInputs;
    });

    "testtools" = python.overrideDerivation super."testtools" (old: {
      propagatedBuildInputs = pbr pkgs (remove self."unittest2" (remove self."fixtures" old.propagatedBuildInputs));
    });

    "zbase32" = python.overrideDerivation super."zbase32" (old: {
      propagatedBuildInputs = remove self."pyutil" old.propagatedBuildInputs;
    });

    "mock" = python.overrideDerivation super."mock" (old: {
      propagatedBuildInputs = pbr pkgs (remove self."unittest2" old.propagatedBuildInputs);
    });

    "oauthlib" = python.overrideDerivation super."oauthlib" (old: {
      propagatedBuildInputs = remove self."unittest2" old.propagatedBuildInputs;
    });
  }