code: def load(cls, env):  # type: (Env) -> InstalledRepository
          
          repo = cls()
  
          freeze_output = env.run("pip", "freeze")
          for line in freeze_output.split("\n"):
              if "==" in line:
                  name, version = re.split("={2,3}", line)
                  repo.add_package(Package(name, version, version))
              elif line.startswith("-e "):
                  line = line[3:].strip()
                  if line.startswith("git+"):
                      url = line.lstrip("git+")
                      if "@" in url:
                          url, rev = url.rsplit("@", 1)
                      else:
                          rev = "master"
  
                      name = url.split("/")[-1].rstrip(".git")
                      if "#egg=" in rev:
                          rev, name = rev.split("#egg=")
  
                      package = Package(name, "0.0.0")
                      package.source_type = "git"
                      package.source_url = url
                      package.source_reference = rev
  
                      repo.add_package(package)
  
          return repo
docs: Load installed packages.
  
          For now, it uses the pip "freeze" command.