from typing import List


def sequence_to_ngram(sequence: str, N: int) -> List[str]:
    """
    Chops a sequence into overlapping N-grams (substrings of length N)

    :param sequence: str Sequence to convert to N-garm
    :type sequence: str
    :param N: Length ofN-grams (int)
    :type N: int
    :return: List of n-grams
    :rtype: List[str]
    """
    return [sequence[i : i + N] for i in range(len(sequence) - N + 1)]