code: public static String getProblemFromFile(Class<?> koanClass, String methodName) {
          return getSourceFromFile(koanClass, methodName, PROBLEM_EXTENSION);
      }
docs: Gets problem for a koan by method name.
  
  @param koanClass the koan class
  @param methodName the method name of the problem required
  @return the problem content to be inserted between the koan start and end markers