   @doc """
   Places a bomb on the board square at the given coordinate.
 
-  Returns `:ok` on success, or `{:error, :invalid_coord}` on failure.
-  """
-  @spec place_bomb(pid, coord) :: :ok | {:error, :invalid_coord}
+  Returns `:ok` on success, or `{:error, :badarg}` on failure.
+  """
+  @spec place_bomb(pid, coord) :: :ok | {:error, :badarg}
   def place_bomb(pid, coord) do
     place_bombs(pid, [coord])
   end

      end)

    if any_errors? do
      {:error, :invalid_coord}
    else
      parsed_coords
      |> Keyword.values

  end

  @doc """
  Parses and normalizes a given coordinate.

  It will parse any of the valid `LexibombServer.Board.coord` forms and will
  normalize them to the underlying `LexibombServer.Board.Grid.coord` type. If
