code: def get_variant_id(variant_dict=None, variant_line=None):
      
      
      if variant_dict:
          chrom = variant_dict['CHROM']
          position = variant_dict['POS']
          ref = variant_dict['REF']
          alt = variant_dict['ALT']
      elif variant_line:
          splitted_line = variant_line.rstrip().split('\t')
          chrom = splitted_line[0]
          position = splitted_line[1]
          ref = splitted_line[3]
          alt = splitted_line[4]
      else:
          raise Exception("Have to provide variant dict or variant line")
      
      return '_'.join([
          chrom,
          position,
          ref,
          alt,
      ])
docs: Build a variant id
      
          The variant id is a string made of CHROM_POS_REF_ALT
          
          Args:
              variant_dict (dict): A variant dictionary
          
          Returns:
              variant_id (str)