docs: def get_file_handle(file_path):
      """Return cyvcf2 VCF object
  
      Args:
          file_path(str)
  
      Returns:
          vcf_obj(cyvcf2.VCF)
      """
      LOG.debug("Check if file end is correct")
  
      if not os.path.exists(file_path):
          raise IOError("No such file:{0}".format(file_path))
  
      if not os.path.splitext(file_path)[-1] in VALID_ENDINGS:
          raise IOError("Not a valid vcf file name: {}".format(file_path))
  
      vcf_obj = VCF(file_path)
  
      return vcf_obj