Raises for a gmail message labeled with "=(-:<"

[antifuchs]

Just tried to import my gmail mailstore, and got this error:

; scanned 561, indexed 561, skipped 0 bad and 0 seen messages in 44.1s = 12.7 m/s
; requesting messages 779..798 from imap server
; got 20 messages
* wrote broken message to bad-message.txt
/Users/asf/Hacks/heliotrope/lib/heliotrope/meta-index.rb:447:in `block in add_labels_to_labellist!': -:< is an invalid label (Heliotrope::MetaIndex::InvalidLabelError)
        from /Users/asf/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/set.rb:222:in `block in each'
        from /Users/asf/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/set.rb:222:in `each_key'
        from /Users/asf/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/set.rb:222:in `each'
        from /Users/asf/Hacks/heliotrope/lib/heliotrope/meta-index.rb:447:in `add_labels_to_labellist!'
        from /Users/asf/Hacks/heliotrope/lib/heliotrope/meta-index.rb:147:in `add_message'
        from bin/heliotrope-import:133:in `block in <main>'
        from /Users/asf/Hacks/heliotrope/lib/heliotrope/message-adder.rb:57:in `block in each_message'
        from /Users/asf/Hacks/heliotrope/lib/heliotrope/imap-dumper.rb:149:in `each_message'
        from /Users/asf/Hacks/heliotrope/lib/heliotrope/message-adder.rb:42:in `each_message'
        from bin/heliotrope-import:109:in `<main>'

I'm kiiind of attached to this label, any way to support it? Thanks!