anchor.diff:  
   % last prime in prime_cache/0
   -define(PrimeCache, 5003).
  -
  -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  -
  --spec get_nearest_feeder(1..5250) -> {1..5250}.
  +-define(TESTER_MAX_PRIME, 5250).
  +
  +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  +
  +-spec get_nearest_feeder(1..?TESTER_MAX_PRIME) -> {1..?TESTER_MAX_PRIME}.
   get_nearest_feeder(N) -> {N}.
   
   % @doc returns first prime larger than N
  
positive.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec is_prime_feeder(1..5250) -> {1..5250}.
  is_prime_feeder(N) -> {N}.
  
  -spec is_prime(pos_integer()) -> boolean().
  
negative.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec get_feeder(1..?TESTER_MAX_PRIME) -> {1..?TESTER_MAX_PRIME}.
  get_feeder(N) -> {N}.
      
  % @doc returns all primes less than or equal to N
  