'Merge in the data from another CoverageResults'

def update(self, other):

    counts = self.counts
    calledfuncs = self.calledfuncs
    callers = self.callers
    other_counts = other.counts
    other_calledfuncs = other.calledfuncs
    other_callers = other.callers
    for key in other_counts.keys():
        counts[key] = (counts.get(key, 0) + other_counts[key])
    for key in other_calledfuncs.keys():
        calledfuncs[key] = 1
    for key in other_callers.keys():
        callers[key] = 1
