   end
 
   @doc """
-  Returns whether a given key exists in the given keywords.
+  Returns whether a given `key` exists in the given `keywords`.
 
   ## Examples
 

  end

  @doc """
  Deletes all entries in the keyword list for a specific key.
  If the key does not exist, returns the keyword list unchanged.
  Use `delete_first` to delete just the first entry in case of
  duplicated keys.


  end

  @doc """
  Deletes the first entry in the keyword list for a specific `key`.
  If the `key` does not exist, returns the keyword list unchanged.

  ## Examples

