code: public static BooleanIsEqual isEqual(BooleanExpression left, Object constant) {
  
          if (!(constant instanceof Boolean))
              throw new IllegalArgumentException("constant is not a Boolean");
  
          return new BooleanIsEqual(left, constant((Boolean)constant));
      }
docs: Creates an IsEqual expression from the given expression and constant.
  
  @param left  The left expression.
  @param constant The constant to compare to (must be a Boolean).
  @throws IllegalArgumentException If constant is not a Boolean.
  @return A new IsEqual binary expression.