def format_dict(
    adict,
    prefix=' ',
    indent=' ',
    bullets=('', ''),
    excludes=('_',),
    linelen=79,
    trim=1,
):
    """Return pretty-print of nested dictionary."""
    result = []
    for k, v in sorted(adict.items(), key=lambda x: str(x[0]).lower()):
        if any(k.startswith(e) for e in excludes):
            continue
        if isinstance(v, dict):
            v = '\n' + format_dict(
                v, prefix=prefix + indent, excludes=excludes, trim=0
            )
            result.append(f'{prefix}{bullets[1]}{k}: {v}')
        else:
            result.append((f'{prefix}{bullets[0]}{k}: {v}')[:linelen].rstrip())
    if trim > 0:
        result[0] = result[0][trim:]
    return '\n'.join(result)