<prompt> Pedzisa mutsara unotevera: Walker akapiwa nguva yakazara yeFormula One kuti atyaire Lotus 72 mumwaka wa1972, semutyairi wechipiri kuna Emerson Fittipaldi. Zvisinei, sezvo mwaka waipfuurira, vose vari vaviri Walker nechikwata vakatanga kuora mwoyo zvikuru. Pashure pokunge Lotus yawana kuti Walker akanga aedza motokari yeFormula Two yeimwe timu, akabviswa muchikwata nokuda kwe  <response>: GMP yeItaly uye GMP yeCanada, kwaakatsiviwa naReine Wisell. Walker akanga adzoka nokuda kweUS GP, asi akarega basa. 