IMT_MAP = {'ai': 'application/postscript', 'aif': 'audio/x-aiff', 'aifc': 'audio/x-aiff', 'aiff': 'audio/x-aiff', 'asc': 'text/plain', 'au': 'audio/basic', 'avi': 'video/x-msvideo', 'bcpio': 'application/x-bcpio', 'bin': 'application/octet-stream', 'bmp': 'image/bmp', ...}