'Automatically returns the values for the given keyword attribute for
all `Column`s in this list.
Implements for example self.units, self.formats, etc.'

def __getattr__(self, name):

    cname = name[:(-1)]
    if ((cname in KEYWORD_ATTRIBUTES) and (name[(-1)] == 's')):
        attr = []
        for col in self.columns:
            val = getattr(col, cname)
            attr.append((val if (val is not None) else ''))
        return attr
    raise AttributeError(name)
