<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def fix_input_files_for_variadic_seq(headerDir, sourceDir, timestamp):
 """Fixes files used as input when pre-processing MPL-containers in their variadic form."""

    # Fix files in include/source-directories.
    files  = glob.glob( os.path.join( headerDir, "*.hpp" ) )
    files += glob.glob( os.path.join( headerDir, "aux_", "*.hpp" ) )
    files += glob.glob( os.path.join( sourceDir, "src", "*" ) )
    for currentFile in sorted( files ):
        fix_header_comment( currentFile, timestamp )