def chop_sequence(sequence: str, peptide_length: int) -> list:
    """
    Chops sequence into N fragments of peptide_length.

    :param sequence: Amino acid sequence
    :param peptide_length: Length of fragments
    :return: list
    """
    if len(sequence) < peptide_length:
        raise ValueError(f'sequence is shorter than peptide_length')
    fragments = []
    for i in range(len(sequence) - peptide_length + 1):
        peptide = sequence[i: i+peptide_length]
        fragments.append(peptide)
    return fragments