The business partner of a former state lawmaker has been sentenced to two years, three months, in federal prison for his part in a scheme to underreport nearly $1.8 million in receipts from their insurance adjustment business. William L’Europa, 47, of Scituate was sentenced Wednesday in US District Court in Providence. He pleaded guilty in September to conspiracy and tax fraud charges. He must also serve three years of supervised release. Prosecutors said L’Europa and his partner, former deputy House speaker John McCauley, filed false returns for tax years 2007 to 2010 and cheated the government out of more than $500,000 in tax payments.