anchor.diff:      pynacl
       pysaml2
       pyyaml
  -    service-identity
       signedjson
       twisted
       ujson
  
positive.code: }:
  
  let
    version = "0.18.4";
  in
  buildPythonPackage {
    name = "synapse-${version}";
  
negative.code:     canonicaljson
      daemonize
      jinja2
      matrix-angular-sdk
      matrix-synapse-ldap3
      msgpack-python
      netaddr
      pillow
  