document.save("output.pdf") RuntimeError: Proxy error(ArgumentNullException): Value cannot be null. (Parameter 'key')

Question

I have the following code:

import aspose.pdf as pdf

# Load input PDF document
document = pdf.Document("some_pdf.pdf")

# Initialize the TeXSaveOptions
texSaveOptions = pdf.TeXSaveOptions()

# Convert the PDF to TEX file
document.save("PDFToTEX.tex", texSaveOptions)

print("Rendering process completed")

When saving the document using aspose.pdf it gives the error as Value cannot be null. Using the latest version for aspose.pdf

I tried to add license and play over it. Did not help. However aspose.words works as exptected.