Change the way parent_key value is assigned

[bilalebi]

JIRA Ticket

https://www.ebi.ac.uk/panda/jira/browse/EA-1240

Changes

Example query

query pig_query {
  genomes(by_keyword: { common_name: "pig" }) {
    assembly_accession
    dataset {
      dataset_id
      dataset_type
      name
      release
      release_date
      release_type
      source
      type
      version
    }
    genome_id
    genome_tag
    is_reference
    parlance_name
    release_date
    release_number
    scientific_name
    taxon_id
    tol_id
    assembly {
      accession_id
      accessioning_body
      assembly_id
      default
      name
      organism {
        is_reference_organism
        scientific_name
        scientific_parlance_name
        assemblies {
          organism {
            assemblies {
              tolid
            }
          }
        }
      }
    }
  }
}

This query fetches many assemblies from both 110.2 and 110.2 releases.

From dict.setdefault docs:

If key is in the dictionary, return its value. If not, insert key with a value of default and return default. default defaults to None.

In our case, info.context[parent_key] was already set in the previous loop executions (e.g pointing to release 110.1 collection), which means info.context.setdefault(parent_key, conn) will be ignored, we need to update it if the release number changes