Checks if a schema exists on the Postgres server.

    CLI Example:

    .. code-block:: bash

        salt '*' postgres.schema_exists dbname schemaname

    dbname
        Database name we query on

    name
       Schema name we look for

    user
        The system user the operation should be performed on behalf of

    db_user
        database username if different from config or default

    db_password
        user password if any password for a specified user

    db_host
        Database host if different from config or default

    db_port
        Database port if different from config or default

def schema_exists(dbname, name, user=None,
                  db_user=None, db_password=None,
                  db_host=None, db_port=None):
    '''
    Checks if a schema exists on the Postgres server.

    CLI Example:

    .. code-block:: bash

        salt '*' postgres.schema_exists dbname schemaname

    dbname
        Database name we query on

    name
       Schema name we look for

    user
        The system user the operation should be performed on behalf of

    db_user
        database username if different from config or default

    db_password
        user password if any password for a specified user

    db_host
        Database host if different from config or default

    db_port
        Database port if different from config or default

    '''
    return bool(
        schema_get(dbname, name, user=user,
                   db_user=db_user,
                   db_host=db_host,
                   db_port=db_port,
                   db_password=db_password))