code: def Presentation(pptx=None):
      
      if pptx is None:
          pptx = _default_pptx_path()
  
      presentation_part = Package.open(pptx).main_document_part
  
      if not _is_pptx_package(presentation_part):
          tmpl = "file '%s' is not a PowerPoint file, content type is '%s'"
          raise ValueError(tmpl % (pptx, presentation_part.content_type))
  
      return presentation_part.presentation
docs: Return a |Presentation| object loaded from *pptx*, where *pptx* can be
      either a path to a ``.pptx`` file (a string) or a file-like object. If
      *pptx* is missing or ``None``, the built-in default presentation
      "template" is loaded.