code: def execute(self):
      
      teardown_verbosity = self._vars.PEX_TEARDOWN_VERBOSE
      try:
        pex_inherit_path = self._vars.PEX_INHERIT_PATH
        if pex_inherit_path == "false":
          pex_inherit_path = self._pex_info.inherit_path
        self.patch_sys(pex_inherit_path)
        working_set = self._activate()
        self.patch_pkg_resources(working_set)
        exit_code = self._wrap_coverage(self._wrap_profiling, self._execute)
        if exit_code:
          sys.exit(exit_code)
      except Exception:
        # Allow the current sys.excepthook to handle this app exception before we tear things down in
        # finally, then reraise so that the exit status is reflected correctly.
        sys.excepthook(*sys.exc_info())
        raise
      except SystemExit as se:
        # Print a SystemExit error message, avoiding a traceback in python3.
        # This must happen here, as sys.stderr is about to be torn down
        if not isinstance(se.code, int) and se.code is not None:
          print(se.code, file=sys.stderr)
        raise
      finally:
        # squash all exceptions on interpreter teardown -- the primary type here are
        # atexit handlers failing to run because of things such as:
        #   http://stackoverflow.com/questions/2572172/referencing-other-modules-in-atexit
        if not teardown_verbosity:
          sys.stderr.flush()
          sys.stderr = DevNull()
          sys.excepthook = lambda *a, **kw: None
docs: Execute the PEX.
  
      This function makes assumptions that it is the last function called by
      the interpreter.