code: def convert_dms_string_to_dd(dms):
          
          degree_mark_offset = dms.find(u'°')
          degrees = float(dms[:degree_mark_offset].strip())
          minute_mark_offset = dms.find(u"'")
          minutes = float(dms[degree_mark_offset + 1:minute_mark_offset].strip())
          second_mark_offset = dms.find(u'"')
          seconds = float(dms[minute_mark_offset + 1:second_mark_offset].strip())
          return degrees + (minutes / 60) + (seconds / 3600)
docs: Convert a degrees, minutes, and seconds (DMS) string representation,
          such as 38° 53' 23" N, to a decimal degrees (DD), which expresses
          latitude and longitude geographic coordinates as decimal fraction.
  
          @param dms: degrees, minutes, and seconds (DMS) string representation
              of a location on the Earth.
  
          @return: decimal degrees of the geographic coordinates of a location.