from typing import List
import re


def get_starts(expression: str, text: str) -> List[int]:
    """Get the starting positions of the occurrences of 'expression' within
        'text'

    Args:
        expression (str): expression we are searchin within the text.
        text (str): text where the expression should be found.

    Returns:
        List[int]: List of indexes indicating the starting of each found
            expression.
    """

    return [m.start() for m in re.finditer(expression, text)]