code: def unsplit_query(query):
      
      def unsplit_assignment((x, y)):
          if (x is not None) and (y is not None):
              return x + '=' + y
          elif x is not None:
              return x
          elif y is not None:
              return '=' + y
          else:
              return ''
      return '&'.join(map(unsplit_assignment, query))
docs: Create a query string using the tuple query with a format as the one
      returned by split_query()