code: static Set<Integer> findReturnsAndThrows(final List<Instruction> instructions) {
          return find(instruction -> instruction.getType() == Instruction.InstructionType.RETURN || instruction.getType() == Instruction.InstructionType.THROW, instructions);
      }
docs: Searches for return instructions in the given instructions.
  
  @param instructions The instructions where to search
  @return The positions of all found return instructions