docs: def variants(ctx, variant_id, chromosome, end_chromosome, start, end, variant_type,
               sv_type):
      """Display variants in the database."""
      if sv_type:
          variant_type = 'sv'
  
      adapter = ctx.obj['adapter']
  
      if (start or end):
          if not (chromosome and start and end):
              LOG.warning("Regions must be specified with chromosome, start and end")
              return
  
      if variant_id:
          variant = adapter.get_variant({'_id':variant_id})
          if variant:
              click.echo(variant)
          else:
              LOG.info("Variant {0} does not exist in database".format(variant_id))
          return
  
      if variant_type == 'snv':
          result = adapter.get_variants(
              chromosome=chromosome,
              start=start,
              end=end
          )
      else:
          LOG.info("Search for svs")
          result = adapter.get_sv_variants(
              chromosome=chromosome,
              end_chromosome=end_chromosome,
              sv_type=sv_type,
              pos=start,
              end=end
          )
  
      i = 0
      for variant in result:
          i += 1
          pp(variant)
  
      LOG.info("Number of variants found in database: %s", i)