input: Write a python function to generate and write to multiple files based on the provided code and check if the files contain the expected content.
  assert generate_files() is None
  assert os.path.exists("RelCASPT2_make_xq.cc")
  assert os.path.exists("RelCASPT2_make_yq.cc")
  assert os.path.exists("RelCASPT2.cc")
  with open("RelCASPT2_make_xq.cc", "r") as file:
      content = file.read()
      assert "// Filename: RelCASPT2_make_xq.cc" in content
  with open("RelCASPT2_make_yq.cc", "r") as file:
      content = file.read()
      assert "// Filename: RelCASPT2_make_yq.cc" in content
output: import os
  
  def generate_files():
      filenames = ["RelCASPT2_make_xq.cc", "RelCASPT2_make_yq.cc", "RelCASPT2.cc"]
      for filename in filenames:
          with open(filename, "w") as file:
              file.write(f"// Filename: {filename}\n")