code: public static final Assignment fromSortedArrays(int[] vars, Object[] values) {
      // Verify that the assignment is sorted and contains no duplicate values.
      for (int i = 1; i < vars.length; i++) {
        Preconditions.checkArgument(vars[i - 1] < vars[i], "Illegal assignment variable nums: %s %s",
            vars[i - 1], vars[i]);
      }
      return new Assignment(vars, values);
    }
docs: Creates an {@code Assignment} mapping each variable in {@code vars} to
  the value at the corresponding index of {@code values}. {@code vars}
  must be sorted in ascending order. This method does not copy either
  {@code vars} or {@code values}; the caller should not read or modify
  either of these arrays after invoking this method.
  
  @param vars
  @param values
  @return