mr() is deprecated and will be removed in v0.6.0. Use mrjob.step.MRStep directly instead.

MRStep.py

from mrjob.job import MRJob
from mrjob.step import MRStep

    def steps(self):
        return [
            MRStep(mapper=self.myMapper,
                    combiner=self.myCombiner,
                    reducer=self.myReducer)
        ]