Add contents of specified columns in .csv file to a list of dictionaries

importcsv.py

import csv


def import_csv(filename=None, import_all_columns=False, columns_to_import=None, remove_duplicates=False):
    """
    Add contents of specified columns in .csv file to a list of dictionaries.
    
    :param filename: string
    :param import_all_columns: bool
    :param columns_to_import: list
    :param remove_duplicates: bool
    :return: list of dictionaries
    """
    # Avoid mutable function defaults
    if columns_to_import is None:
        columns_to_import = []
    results = []
    with open(filename, 'rb') as c:
        csv_reader = csv.DictReader(c)
        for row in csv_reader:
            if import_all_columns:
                results.append(row)
            else:
                results.append({key: value for (key, value) in row.items() if key in columns_to_import})
    if remove_duplicates:
        return [dict(t) for t in set([tuple(d.items()) for d in results])]
    return results