code: def run_solr_on(solrInstance, category, id, fields):
      
      query = solrInstance.value + "select?q=*:*&fq=document_category:\"" + category.value + "\"&fq=id:\"" + id + "\"&fl=" + fields + "&wt=json&indent=on"
      response = requests.get(query)
      return response.json()['response']['docs'][0]
docs: Return the result of a solr query on the given solrInstance (Enum ESOLR), for a certain document_category (ESOLRDoc) and id