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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 generate_migration_name(self, name, suffix):
 """Returns a name of a new migration. It will usually be a filename with a valid and unique name. :param name: human-readable name of a migration :param suffix: file suffix (extension) - eg. 'sql' """

        return os.path.join(self.dir,
                            'm{datestr}_{name}.{suffix}'.format(
                                datestr=datetime.datetime.utcnow().strftime('%Y%m%d%H%M%S'),
                                name=name.replace(' ', '_'),
                                suffix=suffix))