isApproximatelyEqualTo(other, epsilon) {
        if (other instanceof Complex || typeof other === "number") {
            let d = this.minus(Complex.from(other));
            return Math.abs(d.real) <= epsilon &&
                Math.abs(d.imag) <= epsilon &&
                d.abs() <= epsilon;
        }
        return false;
    }
Determines if the receiving complex value is near the given complex, integer, or float value.
This method returns false, instead of throwing, when given badly typed arguments.
@param {!number|!Complex|*} other
@param {!number} epsilon
@returns {!boolean}