code: public double probability(double x0, double x1) {
          if (x0 > x1) {
              throw new NumberIsTooLargeException(LocalizedFormats.LOWER_ENDPOINT_ABOVE_UPPER_ENDPOINT, x0, x1, true);
          }
          return cumulativeProbability(x1) - cumulativeProbability(x0);
      }
docs: For a random variable {@code X} whose values are distributed according
  to this distribution, this method returns {@code P(x0 < X <= x1)}.
  
  @param x0 Lower bound (excluded).
  @param x1 Upper bound (included).
  @return the probability that a random variable with this distribution
  takes a value between {@code x0} and {@code x1}, excluding the lower
  and including the upper endpoint.
  @throws org.apache.commons.math3.exception.NumberIsTooLargeException if {@code x0 > x1}.
  <p/>
  The default implementation uses the identity
  {@code P(x0 < X <= x1) = P(X <= x1) - P(X <= x0)}
  @since 3.1