Keyword.replace

You're seeing just the function replace, go back to Keyword module for more information.
Link to this function

replace(keywords, key, value)

View Source (since 1.11.0)

Specs

replace(t(), key(), value()) :: t()

Puts a value under key only if the key already exists in keywords.

In the case a value is stored multiple times in the keyword list, later occurrences are removed.

Examples

iex> Keyword.replace([a: 1, b: 2, a: 4], :a, 3)
[a: 3, b: 2]

iex> Keyword.replace([a: 1], :b, 2)
[a: 1]