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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def packageOf(self, dotted_name, packagelevel=None):
 """Determine the package that contains ``dotted_name``."""

        if '.' not in dotted_name:
            return dotted_name
        if not self.isPackage(dotted_name):
            dotted_name = '.'.join(dotted_name.split('.')[:-1])
        if packagelevel:
            dotted_name = '.'.join(dotted_name.split('.')[:packagelevel])
        return dotted_name