def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def dframe(cls, dataset, dimensions):
        if dimensions:
            return dataset.data[dimensions].to_pandas()
        else:
            return dataset.data.to_pandas()