old_contents: """
  Copyright [2009-2017] EMBL-European Bioinformatics Institute
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
       http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  """
  
  import datetime
  
  from django.db import models
  
  
  class RnaPrecomputed(models.Model):
      """
      Contains 2 types of entries: species-specific (taxid != Null) and non-species-specific (taxid == Null).
  
      For every Rna there should be 1 entry in RnaPrecomputed, where taxid = Null and some species-specific.
      """
      id = models.CharField(max_length=22, primary_key=True)  # id = upi + taxid if taxid != Null else upi
      taxid = models.IntegerField(db_index=True, null=True)
      description = models.CharField(max_length=250, null=True)
      upi = models.ForeignKey('Rna', db_column='upi', to_field='upi', related_name='precomputed')
      rna_type = models.CharField(max_length=250, null=True)
      rfam_problems = models.TextField(null=True)
      update_date = models.DateField(null=True)
      has_coordinates = models.BooleanField()
      databases = models.TextField(null=True)
      is_active = models.BooleanField()
      last_release = models.IntegerField(null=True)
      short_description = models.CharField(max_length=250)
  
      update_date = models.DateField(null=False, default=datetime.date(1970, 1, 1))
  
      class Meta:
          db_table = 'rnc_rna_precomputed'
  
new_contents: """
  Copyright [2009-2017] EMBL-European Bioinformatics Institute
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
       http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  """
  
  import datetime
  
  from django.db import models
  
  
  class RnaPrecomputed(models.Model):
      """
      Contains 2 types of entries: species-specific (taxid != Null) and non-species-specific (taxid == Null).
  
      For every Rna there should be 1 entry in RnaPrecomputed, where taxid = Null and some species-specific.
      """
      id = models.CharField(max_length=22, primary_key=True)  # id = upi + taxid if taxid != Null else upi
      taxid = models.IntegerField(db_index=True, null=True)
      description = models.CharField(max_length=250, null=True)
      upi = models.ForeignKey('Rna', db_column='upi', to_field='upi', related_name='precomputed')
      rna_type = models.CharField(max_length=250, null=True)
      rfam_problems = models.TextField(null=True)
      update_date = models.DateField(null=True)
      has_coordinates = models.BooleanField()
      databases = models.TextField(null=True)
      is_active = models.BooleanField()
      last_release = models.IntegerField(null=True)
      short_description = models.CharField(max_length=250)
  
      update_date = models.DateField(null=False, default=datetime.date(1970, 1, 1))
  
      class Meta:
          db_table = 'rnc_rna_precomputed'
  
  
      def get_databases(self):
          return self.databases.split(',')
  
subject: Add a utility function for retrieving precomputed databases as an array