import re


def searchOnePepInOneProt(strProtSeq, strPepSeq):
    """ Finds the  occurances of strPepSeq in strProtSeq.
    Returns:
        listMatches: list containing pairs of begin,end for matching locations.
    """

    listMatches = []
    for match in re.finditer(strPepSeq, strProtSeq):
        start, end = match.span()
        listMatches = listMatches + [[start, end-start]]
    
    return listMatches