docs: def fieldValues(self, name, q="*:*", fq=None, maxvalues=-1):
          """Retrieve the unique values for a field, along with their usage counts.
          http://localhost:8080/solr/select/?q=*:*&rows=0&facet=true&inde
          nt=on&wt=python&facet.field=genus_s&facet.limit=10&facet.zeros=false&fa
          cet.sort=false.
  
          @param name(string) Name of field to retrieve values for
          @param q(string) Query identifying the records from which values will be retrieved
          @param fq(string) Filter query restricting operation of query
          @param maxvalues(int) Maximum number of values to retrieve.  Default is -1,
            which causes retrieval of all values.
          @return dict of {fieldname: [[value, count], ... ], }
  
          """
          params = {
              'q': q,
              'rows': '0',
              'facet': 'true',
              'facet.field': name,
              'facet.limit': str(maxvalues),
              'facet.zeros': 'false',
              'wt': 'python',
              'facet.sort': 'false',
          }
          if fq is not None:
              params['fq'] = fq
          request = urllib.parse.urlencode(params, doseq=True)
          rsp = self.doPost(self.solrBase + '', request, self.formheaders)
          data = eval(rsp.read())
          return data['facet_counts']['facet_fields']