def taxon_database(name, database=None):
    """
    Make a taxon database

    :param name: [String] A database name
    :param url: [String] The database URL
    :param description: [String] A description
    :param id_regex: [String] id regex

    :return: A dict

    Usage::

        from pytaxa import constructors as cs
        cs.taxon_database("ncbi", 
            "http://www.ncbi.nlm.nih.gov/taxonomy",
            "NCBI Taxonomy Database", 
            "*")
    """
    return {'name': name, 'database': database}
