'flatten' TMS nested xyz to single directory structure

flattenTMS

def flattenTMS(tilepath,zoom,voc):
        """flatten the TMS tile structure to put all images in one directory
                e.g. tilepath='tiles', zoom='18'"""
        import glob,os
        for i in glob.glob(tilepath+'/'+zoom+'/*/*png'):
                filename_split = os.path.splitext(i)
                filename_zero, fileext = filename_split
                basename = os.path.basename(filename_zero)
                strn=i.split('/')[-3]+'_'+i.split('/')[-2]+'_'+i.split('/')[-1]
                #write_xml_annotation(strn, boxCoords)
                if not os.path.exists(voc+'JPEGImages/'):
                        os.mkdir(tilevocath+'JPEGImages/')
                os.system('cp '+i+' '+voc+'JPEGImages/'+strn)
                os.system('mogrify -format jpg '+voc+'JPEGImages/'*.png')

flattenTMS('tiles/','19','VOC1900/')