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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def assert_processor_available(processor: str) -> None: """ Assert that a specific PDF processor is available. Args: processor: a PDF processor type from :class:`Processors` Raises: AssertionError: if bad ``processor`` RuntimeError: if requested processor is unavailable """

    if processor not in [Processors.XHTML2PDF,
                         Processors.WEASYPRINT,
                         Processors.PDFKIT]:
        raise AssertionError("rnc_pdf.set_pdf_processor: invalid PDF processor"
                             " specified")
    if processor == Processors.WEASYPRINT and not weasyprint:
        raise RuntimeError("rnc_pdf: Weasyprint requested, but not available")
    if processor == Processors.XHTML2PDF and not xhtml2pdf:
        raise RuntimeError("rnc_pdf: xhtml2pdf requested, but not available")
    if processor == Processors.PDFKIT and not pdfkit:
        raise RuntimeError("rnc_pdf: pdfkit requested, but not available")