from typing import List


def get_indices(text: str, sub: str) -> List[str]:
    """Gets all the indexes of occurrence of 'sub' in 'text'"""

    indices = []
    processed_chars = 0
    working_part = text

    while sub in working_part:
        idx = processed_chars + working_part.index(sub)
        indices.append(idx)
        processed_chars = idx + len(sub)
        working_part = text[processed_chars:]

    return indices