from typing import OrderedDict
import csv


def get_fields(csv_file, fields):
    """Return a dictionary mapping each name in `fields` to the sequence of
    values seen for that field in the given file.
    """
    result = OrderedDict()
    for field in fields:
        result[field] = []
    
    with open(csv_file) as f:
        reader = csv.DictReader(f)
        for row in reader:
            for field in fields:
                result[field].append(row[field])
    
    return result