OPINION — AG — ** CITIES (MUNICIPALITIES) — PUBLIC COMPETITIVE BIDDING ACT — NEGOTIATION WITH LOW BIDDER ** WHERE A CITY SEEKS CONSTRUCTION BIDS PURSUANT TO 61 O.S. 1976 Supp., 101-136 [61-101-136], THE CITY MAY NOT NEGOTIATE WITH THE LOW BIDDER IF ALL SUBMITTED BIDS EXCEED THE ENGINEER'S ESTIMATE REQUIRED IN 11 O.S. 1971 673 [11-673] CITE: 61 O.S. 1971 119 [61-119] (MIKE D. MARTIN)