text: from django.db import models
  from edge.models import Genome
  
  
  class Operation(models.Model):
      class Meta:
          app_label = "edge"
  
      # numerical values are stored in database, do not change unless you have a
      # plan for migrating data.
      RECOMBINATION = (1, 'Homologous Recombination')
      CRISPR_DSB = (2, 'CRISPR-Cas9 WT (Double Stranded Break)')
      PCR_SEQ_VERIFICATION = (3, 'PCR Product Sequence Verification')
  
      genome = models.ForeignKey(Genome)
      type = models.IntegerField(choices=(RECOMBINATION, CRISPR_DSB, PCR_SEQ_VERIFICATION))
      params = models.TextField(null=True, blank=True)
  