code: def get_full_filename_by_suffixes(dir_src, suffixes):
          # type: (AnyStr, Union[AnyStr, List[AnyStr]]) -> Optional[List[AnyStr]]
          
          file_names = FileClass.get_filename_by_suffixes(dir_src, suffixes)
          if file_names is None:
              return None
          return list(dir_src + os.sep + name for name in file_names)
docs: get full file names with the given suffixes in the given directory
  
          Args:
              dir_src: directory path
              suffixes: wanted suffixes
  
          Returns:
              full file names with the given suffixes as list