Question: 
Please complete the python function and output the entire function within a python code block, without any explainations.
```python
from typing import List

def get_sum(a: List[int]) -> int:
    """calculate the sum of an integer array."""
```

Answer:
```python
def get_sum(a: List[int]):
    sum = 0
        for x in a:
            sum += x
    return sum
```
