human
Solve the following python programming problem given the following code:
# Inspired from stackoverflow.com/questions/25239958
class MostFrequentImputer(BaseEstimator, TransformerMixin):
    def fit(self, X, y=None):
        self.most_frequent = pd.Series([X[c].value_counts().index[0] for c in X],
                                       index=X.columns)
        return self
    def transform(self, X, y=None):
        return X.fillna(self.most_frequent)
Given the above code, generate some markdown instructions for it.
assistant
#Here is the Python program you requested.

We will also need an imputer for the string categorical columns (the regular Imputer does not work on those):