[Python] Turning Letter sized pdfs into B size

I'm trying to make "A"-sized (8.5" x 11") pdfs into "B"-sized (11" x 17") pdfs. Because of their dimensions, I should be able to fit two "A"-sized papers into a single "B"-sized paper. I want the A sized output to be on the right side of the page and left side of the B sized paper to be blank.

I'm updating a program I wrote to put information onto a pdf and want it to convert the A sized papers to B sized as well. Currently, I'm using separate steps to first merge information into an "A"-sized pdf, and then another step to try to merge a blank "B"-sized paper with the "A"-sized paper. Proabably could do this in a single step, but I'm just trying to make this work. Any help would be appreciated.

# Makes a temporary pdf to put text into and merge into another pdf later
c = canvas.Canvas("temp.pdf", pagesize=Pagesize_Canvas)
c.setFont(Font, Font_size)
c.setFillColorRGB(1, 0, 0) # Red color
c.drawString(LABEL_ONE_position_width, LABEL_ONE_position_height, LABEL_ONE) #sets position of LABEL_ONE on back of paper.
c.drawString(LABEL_TWO_position_width, LABEL_TWO_position_height, LABEL_TWO) #sets position of LABEL_TWO on back of paper.
c.save()

temp_pdf = PdfReader(open("temp.pdf", "rb"))
temp_page = temp_pdf.pages[0]


# Merge step
Final_output_pdf = PdfWriter()
for page_num, page in enumerate(existing_pdf.pages):
if page_num >= 0:
page.merge_page(temp_page)
Final_output_pdf.add_page(page)


# Save the output PDF to a file

with open(f"{newpath}\{ROW}_{PART_NUMBER:.0f}_{SHEETCOUNT}.pdf", "wb") as output_file:
Final_output_pdf.write(output_file)

temptwo_pdf = PdfReader(open(f"C:\\Users\\{USERNAME}\\Desktop\\blank_B_size.pdf", "rb"))

# Merge step
Finaltwo_output_pdf = PdfWriter()
for page_num, page in enumerate(Final_output_pdf.pages):
if page_num >= 0:

page.merge_page(temptwo_pdf)
Finaltwo_output_pdf.add_page(page)

with open(f"{newpath}\{ROW}_{PART_NUMBER:.0f}_{SHEETCOUNT}.pdf", "wb") as output_file:
Final_output_pdf.write(output_file)


temptwo_pdf.stream.close()
temp_pdf.stream.close()
os.remove("temp.pdf")

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