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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 availability_pdf() -> bool: """ Is a PDF-to-text tool available? """

    pdftotext = tools['pdftotext']
    if pdftotext:
        return True
    elif pdfminer:
        log.warning("PDF conversion: pdftotext missing; "
                    "using pdfminer (less efficient)")
        return True
    else:
        return False