   @doc """
   Returns all keys from the keyword list.
 
-  Duplicated keys appear duplicated in the final list of keys.
+  Duplicate keys will not be filtered out from the resulting list of keys.
 
   ## Examples
 

  end

  @doc """
  Takes all entries corresponding to the given keys and returns them in a new
  keyword list.

  Duplicated keys are preserved in the new keyword list.

  ## Examples


  @doc """
  Fetches the value for specific `key`.

  If the `key` does not exist, a `KeyError` is raised.

  ## Examples

