def rename_clusters(name_dict, df, column_name):
    """
    Takes in a dataframe, column name of the cluster, dictionary in the format:  {'original_cluster_name' : 'new_cluster_name'}. 
    Returns a dataframe with the new cluster names. 
    """
    df = df.copy()
    
    keys = list(name_dict.keys())
    
    for key in keys:
        df[column_name] = df[column_name].str.replace(key, name_dict[key])
        
    return df