def return_output_format_args(output_format):
    """
        Return bcftools arguments for output format

        Parameters
        ----------
        output_format : str
            The specified output format

        Raises
        ------
        Exception
            If output format is unsupported by bcftools
    """
    if output_format == 'vcf':
        return ['-O', 'v']
    elif output_format == 'bcf':
        return ['-O', 'b']
    elif output_format == 'vcf.gz':
        return ['-O', 'z']
    else:
        raise Exception('Unsupported file format')
