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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 is_package_installed(self, package_name):
 """Check if the RPM package is installed."""

        if not package_name:
            raise ValueError('package_name required.')

        installed = True
        try:
            Cmd.sh_e('{0} --query {1} --quiet'.format(self.rpm_path,
                                                      package_name))
        except InstallError:
            installed = False
        return installed