@classmethod
def read_dataframe(cls, dataframe, wildtype, **kwargs):
    """Construct a GenotypePhenotypeMap from a dataframe."""
    df = dataframe
    self = cls(wildtype, df.genotypes, df.phenotypes, stdeviations=df.
        stdeviations, n_replicates=df.n_replicates, **kwargs)
    return self
