def gt_miss(g):
    """
    Return True if sample genotype is missing.

    Parameters
    ----------
    g : str
        Sample genotype.

    Returns
    -------
    bool
        True if sample genotype is missing.

    Examples
    --------

    >>> from fuc import pyvcf
    >>> pyvcf.gt_miss('0')
    False
    >>> pyvcf.gt_miss('0/0')
    False
    >>> pyvcf.gt_miss('0/1')
    False
    >>> pyvcf.gt_miss('0|0:48:1:51,51')
    False
    >>> pyvcf.gt_miss('./.:.:.')
    True
    >>> pyvcf.gt_miss('.:.')
    True
    >>> pyvcf.gt_miss('.')
    True
    >>> pyvcf.gt_miss('./.:13,3:16:41:41,0,402')
    True
    """
    return '.' in g.split(':')[0]