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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def database_exists(url):
 """Check if a database exists. :param url: A SQLAlchemy engine URL. Performs backend-specific testing to quickly determine if a database exists on the server. :: database_exists('postgres://postgres@localhost/name') #=> False create_database('postgres://postgres@localhost/name') database_exists('postgres://postgres@localhost/name') #=> True Supports checking against a constructed URL as well. :: engine = create_engine('postgres://postgres@localhost/name') database_exists(engine.url) #=> False create_database(engine.url) database_exists(engine.url) #=> True """


    url = copy(make_url(url))
    database = url.database
    if url.drivername.startswith('postgresql'):
        url.database = 'template1'
    else:
        url.database = None

    engine = sa.create_engine(url)

    if engine.dialect.name == 'postgresql':
        text = "SELECT 1 FROM pg_database WHERE datname='%s'" % database
        return bool(engine.execute(text).scalar())

    elif engine.dialect.name == 'mysql':
        text = ("SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA "
                "WHERE SCHEMA_NAME = '%s'" % database)
        return bool(engine.execute(text).scalar())

    elif engine.dialect.name == 'sqlite':
        return database == ':memory:' or os.path.exists(database)

    else:
        text = 'SELECT 1'
        try:
            url.database = database
            engine = sa.create_engine(url)
            engine.execute(text)
            return True

        except (ProgrammingError, OperationalError):
            return False