docs: def env(self):
          """
          Dict of all environment variables that will be run with this command.
          """
          env_vars = os.environ.copy()
          env_vars.update(self._env)
          new_path = ":".join(
              self._paths + [env_vars["PATH"]] if "PATH" in env_vars else [] + self._paths
          )
          env_vars["PATH"] = new_path
          for env_var in self._env_drop:
              if env_var in env_vars:
                  del env_vars[env_var]
          return env_vars