The governing authority of any parish or municipal corporation, the City of New Orleans and Parish of Orleans excepted, may of its own initiative create, establish, equip, maintain, operate and support a public library in such parish or municipality and shall create, establish, equip, maintain, operate and support such a public library when not less than twenty-five per cent of the duly qualified property taxpayers resident in such parish or municipality shall petition the governing authority thereof to establish such a public library for such parish or municipality.  Provided that two or more parishes may join in the establishment of a public library to be supported and maintained by them jointly in the proportions as may be determined by the police juries of the respective parishes or other governing authority; and provided that a parish and one or more municipal corporations may jointly establish, maintain and operate a public library; and provided also one parish or municipality may contract with another parish or municipality to furnish library service upon such terms and conditions and for such considerations as the governing authorities concerned may stipulate and agree by written contract pursuant to ordinances duly passed by them.