code: def find_files(path, exts=None):
      
      files_list = []
      for root, dirs, files in os.walk(path):
          for name in files:
              files_list.append(os.path.join(root, name))
      
      if exts is not None:
          return [file for file in files_list if pathlib.Path(file).suffix in exts]
      
      return files_list
docs: 查找路径下的文件，返回指定类型的文件列表
  
      :param:
          * path: (string) 查找路径
          * exts: (list) 文件类型列表，默认为空
  
      :return:
          * files_list: (list) 文件列表
  
      举例如下::
  
          print('--- find_files demo ---')
          path1 = '/root/fishbase_issue'
          all_files = find_files(path1)
          print(all_files)
          exts_files = find_files(path1, exts=['.png', '.py'])
          print(exts_files)
          print('---')
  
      执行结果::
  
          --- find_files demo ---
          ['/root/fishbase_issue/test.png', '/root/fishbase_issue/head.jpg','/root/fishbase_issue/py/man.png'
          ['/root/fishbase_issue/test.png', '/root/fishbase_issue/py/man.png']
          ---