def mergeDict(recipient_dict, donor_dict):
    """Merge donor_dict into recipient_dict:
       Add new k,v pairs to recipient_dict, 
       update v in recipient_dict if different in donor_dict.
       Return recipient_dict. 
    """
    for k, v in donor_dict.items():
        if k in recipient_dict:
            if recipient_dict[k] != donor_dict[k]:
                recipient_dict[k] = donor_dict[k]
        else:
            recipient_dict[k] = donor_dict[k]
    return(recipient_dict)