docs: def remove_xmlns(xml_string):
          """
          changes the xmlns (XML namespace) so that values are
          replaced with the string representation of their key
          this makes the import process for portable
  
          >>> xp = XML_parser
          >>> test_xmlns = r'<rss version="2.0" xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/">'
          >>> xp.remove_xmlns(test_xmlns)
          '<rss version="2.0" xmlns:excerpt="excerpt">'
          """
          # splitting xml into sections, pre_chan is preamble before <channel>
          pre_chan, chan, post_chan= xml_string.partition('<channel>')
          # replace xmlns statements on preamble
          pre_chan = re.sub(r'xmlns:(?P<label>\w*)\=\"(?P<val>[^\"]*)\"',
                               r'xmlns:\g<label>="\g<label>"',
                               pre_chan)
          # piece back together
          return pre_chan + chan + post_chan