You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: raxml-ng.rb
    path of file: ./repos/homebrew-core/Formula/r
    
    the code of the file until where you have to start completion: class RaxmlNg < Formula
  desc "RAxML Next Generation: fast
    
  def install
    args = std_cmake_args + ["-DUSE_GMP=ON"]
    system "cmake", "-S", ".", "-B", "build", *args
    system "cmake", "--build", "build"
    system "cmake", "--install", "build"

    # Upstream doesn't support building MPI variant on macOS.
    # The build ignores USE_MPI=ON and forces ENABLE_MPI=OFF.
    # This causes necessary flags like -D_RAXML_MPI to not get set.
    return if OS.mac?

    system "cmake", "-S", ".", "-B", "build_mpi", *args, "-DUSE_MPI=ON"
    system "cmake", "--build", "build_mpi"
    system "cmake", "--install", "build_mpi"
  end

  test do
    testpath.install resource("homebrew-example")
    system bin/"raxml-ng", "--msa", "dna.phy", "--start", "--model", "GTR"
  end
end