def csv_to_json(csv_filepath, json_filepath, fieldnames, ignore_first_line=True
    ):
    """ Convert a CSV file in `csv_filepath` into a JSON file in `json_filepath`.

    Parameters
    ----------
    csv_filepath: str
        Path to the input CSV file.

    json_filepath: str
        Path to the output JSON file. Will be overwritten if exists.

    fieldnames: List[str]
        Names of the fields in the CSV file.

    ignore_first_line: bool
    """
    import csv
    import json
    csvfile = open(csv_filepath, 'r')
    jsonfile = open(json_filepath, 'w')
    reader = csv.DictReader(csvfile, fieldnames)
    rows = []
    if ignore_first_line:
        next(reader)
    for row in reader:
        rows.append(row)
    json.dump(rows, jsonfile)
    jsonfile.close()
    csvfile.close()
