53 STAT.] 76TH CONG. , 1ST SESS.-CH. 367-JULY 26, 1939 summoned shall neglect or refuse to obey the summons issued as herein provided, then, and in that event, the assessor may report that fact to the District Court of the United States for the District of Columbia, or one of the justices thereof, and said court or any justice thereof hereby is empowered to compel obedience to such summons to the same extent as witnesses may be compelled to obey the subpenas of that court. Any person in custody or control of any books, papers, records, or memoranda bearing upon the matters required to be included in such returns, who shall refuse to permit the examination by the assessor or any person designated by him of any such books, papers, records, or memoranda, or who shall obstruct or hinder the assessor or any person designated by him in the examina- tion of any books, papers, records, or memoranda, shall upon convic- tion thereof be fined not more than $300. All prosecutions under this section shall be brought in the police court of the District of Columbia on information by the corporation counsel of the District of Columbia in the name of the District of Columbia. (d) RETUTRN BY ASSESSOR. - If any person fails to make and file a return at the time prescribed by law or by regulations made under authority of law, or makes, willfully or otherwise, a false or fraudu- lent return, the assessor shall make the return from his own knowl- edge and from such information as he can obtain through testimony or otherwise. Any return so made and subscribed by the assessor shall be prima facie good and sufficient for all legal purposes. ASSESSMENT AND COLLECION OF DIFICIENsCIE SEC. 30. DEFINITION OF "DEFICIENCY."-As used in this title in respect of a tax imposed by this title "deficiency" means- (1) the amount by which the tax imposed by this title exceeds the amount shown as the tax by the taxpayer upon his return; but the amount so shown on the return shall first be increased by the amounts previously assessed (or collected without assess- ment) as a deficiency, and decreased by the amounts previously abated, credited, refunded, or otherwise repaid in respect of such tax; or (2) if no amount is shown as the tax by the taxpayer upon his return, or if no return is made by the taxpayer, then the amount by which the tax exceeds the amounts previously assessed (or collected without assessment) as a deficiency; but such amounts previously assessed, or collected without assessment, shall first be decreased by the amounts previously abated, credited, refunded, or otherwise repaid in respect of such tax. DETERMINATION AND ASSESSMIENT OF DEFICIENCY SEC. 31. If a deficiency in tax is determined by the assessor, the taxpayer shall be notified thereof and given a period of not less than thirty days, after such notice is sent by registered mail, in which to file a protest and show cause or reason why the deficiency should not be paid. Opportunity for hearing shall be granted by the asses- sor, and a final decision thereon shall be made as quickly as prac- ticable. Any deficiency in tax then determined to be due shall be assessed and paid, together with any addition to the tax applicable thereto, within ten days after notice and demand by the collector. The taxpayer may appeal from such assessment to the Board of Tax Appeals for the District of Columbia in the same manner and to the same extent as set forth in sections 3, 4, 7, 8, 9, 10, 11, and 12 of title IX of an Act to amend the District of Columbia Revenue Act of 1937, and for other purposes, approved May 16, 1938. 1101 Enforcement of orders. Jurisdiction. Return by assessor. "Deficiency" de. fined. Notice to taxpayer. Opportunity f o r hearing allowed. Appeal to Board of Tax Appeals, D. C. 52Stat. 371, 374,375.