docs: def number_of_issues_by_year(self, issn, collection, years=0, type=None):
          """
          type: ['regular', 'supplement', 'pressrelease', 'ahead', 'special']
          """
  
          body = {
              "query": {
                  "bool": {
                      "must": [
                          {
                              "match": {
                                  "issn": issn
                              }
                          },
                          {
                              "match": {
                                  "collection": collection
                              }
                          }
                      ]
                  }
              },
              "aggs": {
                  "issue": {
                      "cardinality": {
                          "field": "issue"
                      }
                  }
              }
  
          }
  
          if type:
              body['query']['bool']['must'].append({"match": {"issue_type": type}})
  
          if years != 0:
              body['aggs'] = {
                  "publication_year": {
                      "terms": {
                          "field": "publication_year",
                          "size": years,
                          "order": {
                              "_term": 'desc'
                          }
                      },
                      "aggs": {
                          "issue": {
                              "cardinality": {
                                  "field": "issue"
                              }
                          }
                      }
                  }
              }
  
          query_parameters = [
              ('size', '0')
          ]
  
          query_result = self.search(
              'article', json.dumps(body), query_parameters
          )
  
          return self._compute_number_of_issues_by_year(
              query_result, years=years)