def _find(delimiter, content, start_index):
    """Given that a string starts at the index specified, scan for the end of that string.
    :param str delimiter: Delimiter for which to search.
    :param str content: String to scan.
    :param int start_index: Index of the character after opening string delimiter.
    :returns: Index of the closing string delimiter.
    """
    index = start_index
    while index < len(content):
        char = content[index]
        if char == '\\':
            index += 1
        elif char == delimiter:
            return index
        index += 1
    raise ValueError()