docs: def copy_files_to(src_fpath_list, dst_dpath=None, dst_fpath_list=None,
                    overwrite=False, verbose=True, veryverbose=False):
      """
      parallel copier
  
      Example:
          >>> # DISABLE_DOCTEST
          >>> from utool.util_path import *
          >>> import utool as ut
          >>> overwrite = False
          >>> veryverbose = False
          >>> verbose = True
          >>> src_fpath_list = [ut.grab_test_imgpath(key)
          >>>                   for key in ut.get_valid_test_imgkeys()]
          >>> dst_dpath = ut.get_app_resource_dir('utool', 'filecopy_tests')
          >>> copy_files_to(src_fpath_list, dst_dpath, overwrite=overwrite,
          >>>               verbose=verbose)
      """
      from utool import util_list
      from utool import util_parallel
  
      if verbose:
          print('[util_path] +--- COPYING FILES ---')
          print('[util_path]  * len(src_fpath_list) = %r' % (len(src_fpath_list)))
          print('[util_path]  * dst_dpath = %r' % (dst_dpath,))
  
      if dst_fpath_list is None:
          ensuredir(dst_dpath, verbose=veryverbose)
          dst_fpath_list = [join(dst_dpath, basename(fpath))
                            for fpath in src_fpath_list]
      else:
          assert dst_dpath is None, 'dst_dpath was specified but overrided'
          assert len(dst_fpath_list) == len(src_fpath_list), 'bad correspondence'
  
      exists_list = list(map(exists, dst_fpath_list))
      if verbose:
          print('[util_path]  * %d files already exist dst_dpath' % (
              sum(exists_list),))
      if not overwrite:
          notexists_list = util_list.not_list(exists_list)
          dst_fpath_list_ = util_list.compress(dst_fpath_list, notexists_list)
          src_fpath_list_ = util_list.compress(src_fpath_list, notexists_list)
      else:
          dst_fpath_list_ = dst_fpath_list
          src_fpath_list_ = src_fpath_list
  
      args_list = zip(src_fpath_list_, dst_fpath_list_)
      _gen = util_parallel.generate2(_copy_worker, args_list,
                                     ntasks=len(src_fpath_list_))
      success_list = list(_gen)
  
      #success_list = copy_list(src_fpath_list_, dst_fpath_list_)
      if verbose:
          print('[util_path]  * Copied %d / %d' % (sum(success_list),
                                                   len(src_fpath_list)))
          print('[util_path] L___ DONE COPYING FILES ___')