docs: def get_sv_variants(self, chromosome=None, end_chromosome=None, sv_type=None, 
                          pos=None, end=None):
          """Return all structural variants in the database
  
          Args:
              chromosome (str)
              end_chromosome (str)
              sv_type (str)
              pos (int): Left position of SV
              end (int): Right position of SV
  
          Returns:
              variants (Iterable(Variant))
          """
          query = {}
          
          if chromosome:
              query['chrom'] = chromosome
          if end_chromosome:
              query['end_chrom'] = end_chromosome
          if sv_type:
              query['sv_type'] = sv_type
          if pos:
              if not '$and' in query:
                  query['$and'] = []
              query['$and'].append({'pos_left': {'$lte': pos}})
              query['$and'].append({'pos_right': {'$gte': pos}})
              
          if end:
              if not '$and' in query:
                  query['$and'] = []
              query['$and'].append({'end_left': {'$lte': end}})
              query['$and'].append({'end_right': {'$gte': end}})
          
          LOG.info("Find all sv variants {}".format(query))
          
          return self.db.structural_variant.find(query).sort([('chrom', ASCENDING), ('pos_left', ASCENDING)])