imaplib.IMAP4.store()

IMAP4.store(message_set, command, flag_list)

Alters flag dispositions for messages in mailbox. command is specified by section 6.4.6 of RFC 2060 as being one of “FLAGS”, “+FLAGS”, or “-FLAGS”, optionally with a suffix of ”.SILENT”.

For example, to set the delete flag on all messages:

typ, data = M.search(None, 'ALL')
for num in data[0].split():
   M.store(num, '+FLAGS', '\\Deleted')
M.expunge()