text: from PyPDF2 import PdfFileMerger
  
  merger = PdfFileMerger()
       
  input1 = open("document1.pdf", "rb")
  input2 = open("document2.pdf", "rb")
  input3 = open("document3.pdf", "rb")
  
  # add the first 3 pages of input1 document to output
  merger.append(fileobj = input1, pages = (0,3))
  
  # insert the first page of input2 into the output beginning after the second page
  merger.merge(position = 2, fileobj = input2, pages = (0,1))
  
  # append entire input3 document to the end of the output document
  merger.append(input3)
  
  # Write to an output PDF document
  output = open("document-output.pdf", "wb")
  merger.write(output)
  