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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 find_classes(self, name=".*", no_external=False):
 """ Find classes by name, using regular expression This method will return all ClassAnalysis Object that match the name of the class. :param name: regular expression for class name (default ".*") :param no_external: Remove external classes from the output (default False) :rtype: generator of `ClassAnalysis` """

        for cname, c in self.classes.items():
            if no_external and isinstance(c.get_vm_class(), ExternalClass):
                continue
            if re.match(name, cname):
                yield c