SQL alchemy geoalchemy selecting geometry array

I’ve created irregular geometry table which contains point array as geometry type column and I’m trying to retrieve points as per measurement point id.

But I’m having an error :

ProgrammingError: (psycopg2.errors.CannotCoerce) cannot cast type geometry[] to geometry
LINE 1: SELECT ST_X(CAST(db.irregular.axises AS geometry(GEOMETR…

This is how it is in database:

     column_name      | data_type | numeric_scale || udt_schema | udt_name  | 
----------------------+-----------+---------------+-------------+------------+
 id                   | integer   |             0 | | pg_catalog | int4      |
 measurement_point_id | integer   |             0 | | pg_catalog | int4      |
 axises               | ARRAY     |               | | public     | _geometry |

This is my irregular table class:

#%% Irregular Class
class Irregular (object):
    measurement_point_id = relationship("measurement_points", back_populates="id")

    def __init__(self,measurement_point_id,axises=None,id= None):
        self.id = id
        self.measurement_point_id = measurement_point_id
        self.axises = axises
        #self.is_xy = xy

#Irregular Object
__tablename__ = 'irregular'
irregular = Table(
    __tablename__,meta,
    Column ('id', Integer, primary_key = True), 
    Column ( 'measurement_point_id',Integer,ForeignKey('measurement_points.id')),
    Column ( 'axises', ARRAY(Geometry('POINT'))),
    #Column ( 'is_xy', Boolean),
)
mapper(Irregular, irregular)

This is how I am trying to get data :

session.query(fns.ST_X(cast(tb.Irregular.axises, geoalchemy2.types.Geometry)),
                             fns.ST_Y(cast(tb.Irregular.axises, geoalchemy2.types.Geometry)).filter(tb.measurement_point_id == id).all()

I removed casting :
ProgrammingError: (psycopg2.errors.UndefinedFunction) function st_x(geometry[]) does not exist
LINE 1: SELECT ST_X(db.irregular.axises) AS "ST_X_1", ST_Y(db…

I think I need to retrieve as tuple array but I couldn’t find how to cast from python side and which function should I use.