environment/lib/python2.7/site-packages/IPython/parallel/apps/launcher.py
def engine_count(self):
        """determine engine count from `engines` dict"""
        count = 0
        for n in self.engines.itervalues():
            if isinstance(n, (tuple,list)):
                n,args = n
            count += n
        return count
def engine_count(self):
        """determine engine count from `engines` dict"""
        count = 0
        for n in self.engines.itervalues():
            if isinstance(n, (tuple,list)):
                n,args = n
            count += n
        return count
determine engine count from `engines` dict