# File lib/parser/builders/default.rb, line 1062
    def begin(begin_t, body, end_t)
      if body.nil?
        # A nil expression: `()'.
        n0(:begin,
          collection_map(begin_t, nil, end_t))
      elsif body.type == :mlhs  ||
           (body.type == :begin &&
            body.loc.begin.nil? && body.loc.end.nil?)
        # Synthesized (begin) from compstmt "a; b" or (mlhs)
        # from multi_lhs "(a, b) = *foo".
        n(body.type, body.children,
          collection_map(begin_t, body.children, end_t))
      else
        n(:begin, [ body ],
          collection_map(begin_t, [ body ], end_t))
      end
    end