human
Can you provide a the Python program you requested given the following:
Complete the below
def make_pdf_to_png_converter():

    ''''Returns a function that converts a pdf file to a png file.'
    '''
assistant
#Here is the Python program you requested.
    tools_available = []
    try:
        check_output([str(u'pdftocairo'), u'-v'], stderr=subprocess.STDOUT)
        tools_available.append(u'pdftocairo')
    except:
        pass
    (gs, ver) = mpl.checkdep_ghostscript()
    if gs:
        tools_available.append(u'gs')
    if (u'pdftocairo' in tools_available):
        def cairo_convert(pdffile, pngfile, dpi):
            cmd = [str(u'pdftocairo'), u'-singlefile', u'-png', u'-r', (u'%d' % dpi), pdffile, os.path.splitext(pngfile)[0]]
            check_output(cmd, stderr=subprocess.STDOUT)
        return cairo_convert
    elif (u'gs' in tools_available):
        def gs_convert(pdffile, pngfile, dpi):
            cmd = [str(gs), u'-dQUIET', u'-dSAFER', u'-dBATCH', u'-dNOPAUSE', u'-dNOPROMPT', u'-sDEVICE=png16m', u'-dUseCIEColor', u'-dTextAlphaBits=4', u'-dGraphicsAlphaBits=4', u'-dDOINTERPOLATE', (u'-sOutputFile=%s' % pngfile), (u'-r%d' % dpi), pdffile]
            check_output(cmd, stderr=subprocess.STDOUT)
        return gs_convert
    else:
        raise RuntimeError(u'No    suitable    pdf    to    png    renderer    found.')