Sippet.Message.fetch_header_back-exclamation-mark

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fetch_header_back!(message, header)

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Specs

fetch_header_back!(t(), header()) :: multiple_value() | no_return()

Fetches the last value of a specific header in the given message, erroring out if message doesn't contain header.

If message contains the given header, the last value is returned, which may be nil case the values list is empty. If message doesn't contain the header, a KeyError exception is raised.