def get_key(rule_tracker, value):
    """
    Given an event index, its corresponding key from the dictionary is returned.

    Parameters:
        rule_tracker (dict): Key-value pairs specific to a rule where key is an activity, pair is an event index
        value (int): Index of event in event log

    Returns:
        key (int): Position of value in rule_tracker
    """
    for key in rule_tracker:
        if rule_tracker[key] == value:
            return key