import re


def get_skip_report_address_by_index(skip_report_list):
    """Parse validator address from skip report.

    Based on the index within the skip report file (each line a report), the
    validator address for this entry gets extracted. In case no address could be
    found, the whole entry could not been parsed or no report for this index
    exists, the address is 'None'.
    """

    def extract_address(index):
        skip_report_entry = (
            skip_report_list[index] if index < len(skip_report_list) else ""
        )
        address_findings = re.findall(
            "^[0-9]+,(0x[0-9,a-f]+?),[0-9,-]+ [0-9,:]+$", skip_report_entry.strip()
        )
        address = address_findings[0] if len(address_findings) == 1 else None
        return address

    return extract_address