Please solve the programming task below using a self-contained code snippet in a markdown code block.

A complex number can be represented as a string on the form "real+imaginaryi" where:

real is the real part and is an integer in the range [-100, 100].
imaginary is the imaginary part and is an integer in the range [-100, 100].
i2 == -1.

Given two complex numbers num1 and num2 as strings, return a string of the complex number that represents their multiplications.
 
Please complete the following python code precisely:
```python
class Solution:
    def complexNumberMultiply(self, num1: str, num2: str) -> str:
```