Keyword.fetch-exclamation-mark

You're seeing just the function fetch-exclamation-mark, go back to Keyword module for more information.

fetch!(keywords, key)

fetch!(t(), key()) :: value()

Fetches the value for specific key.

If key does not exist, a KeyError is raised.

iex> Keyword.fetch!([a: 1], :a)
1
iex> Keyword.fetch!([a: 1], :b)
** (KeyError) key :b not found in: [a: 1]