code: def get_template_path(filename):
      
      if os.path.isfile(filename):
          return os.path.abspath(filename)
      for i in sys.path:
          if os.path.isfile(os.path.join(i, filename)):
              return os.path.abspath(os.path.join(i, filename))
  
      return None
docs: Find raw template in working directory or in sys.path.
  
      template_path from config may refer to templates colocated with the Stacker
      config, or files in remote package_sources. Here, we emulate python module
      loading to find the path to the template.
  
      Args:
          filename (str): Template filename.
  
      Returns:
          Optional[str]: Path to file, or None if no file found