The tax authorized to be levied under Section 1, of this act, shall, when levied, apply to all persons, firms, associations or corporations engaged in the business of furnishing power, light, heat, gas, electricity or water in any city or town, except it shall not apply to any person, firm, association or corporation operating under a valid franchise from said city or town.
Okla. Stat. tit. 68, § 2602