Question: apparently non-existential procedure called by rand

rand := proc(r::{posint, numeric .. numeric}, $)
   1   if nargs = 0 then
   2     RandomTools:-MersenneTwister:-GenerateInteger()
       else
   3     try
   4       if type(r,('numeric') .. ('numeric')) then
   5         if rhs(r) < lhs(r) then
   6           error "invalid range, end points are out of order"
             elif not type(r,('integer') .. ('integer')) then
   7           return () -> RandomTools:-Generate(float(('range') = r,('method') = ('uniform')))
             end if
           end if;
   8       return RandomTools:-MersenneTwister:-NewGenerator(('range') = r)
         catch :
   9       error
         end try
       end if
end proc

RandomTools:-MersenneTwister:-GenerateInteger := proc({range::{integer, integer .. integer} := 1000000000000}, $)
local bits, divisor, offset;
   1   if nargs = 0 then
   2     return MTKernelInterface(4)
       end if;
   3   if type(range,'integer') then
   4     divisor := range;
   5     offset := 0
       else
   6     if rhs(range) < lhs(range) then
   7       error "illegal range, end points out of order"
         end if;
   8     if lhs(range) = rhs(range) then
   9       return lhs(range)
         end if;
  10     offset := lhs(range);
  11     divisor := rhs(range)-offset+1
       end if;
  12   if divisor = 0 then
  13     return offset
       end if;
  14   bits := MTKernelInterface(5,divisor);
  15   MTKernelInterface(6,divisor,bits)+offset
end proc

Error, (in showstat) procedure name expected