Interview Course Based on Story Questions

# Problem statement
In this challenge, you are given two binary numbers as strings. Implement a function that takes these strings as input, performs the binary addition, and returns the output in the form of a string. 


## Input 
The inputs will be two binary numbers in the form of strings called `a` and `b`. For example, consider the following inputs:
```
a = "1010100"
b = "0100011"
```

## Output
The function will return a string that represents the binary number calculated by the addition of the inputs. The following is the output for the inputs mentioned above is given below:

```
"1110111"
```


DIY: Add Binary

Problem statement