'Returns data as specified by kwargs. start_val is the first element to
return and max_vals indicates the number of values to return.
Return value must be a dictionary with the following attributes:
dataset_type, data'

def get_data(self, chrom, start, end, start_val=0, max_vals=sys.maxint, **kwargs):

    iterator = self.get_iterator(chrom, start, end)
    return self.process_data(iterator, start_val, max_vals, **kwargs)
