Django Postgres Exclusion Constraint with ManyToManyField

I would like to use Django Exclusion Constraint with ManyToManyField. Unfortunatelly, so far my efforts were futile. This is my appointment model:

from django.contrib.postgres.constraints import ExclusionConstraint from django.contrib.postgres.fields import DateTimeRangeField, RangeOperators

class Appointment:
    patients = models.ManyToManyField(Patient, related_name='appointments' , blank=True )     
    datetimerange = DateTimeRangeField(null=False, blank = False )
    doctor = models.ForeignKey(Doctor, related_name='doctor_appointments') 

    class Meta: 
        constraints = [ 
            ExclusionConstraint(
                name='unique_doctor',
                expressions=[
                    ('datetimerange', RangeOperators.OVERLAPS),
                    ('doctor ', RangeOperators.EQUAL),

                ], 
            ), 
            ExclusionConstraint(
                name='unique_patients',
                expressions=[
                    ('datetimerange', RangeOperators.OVERLAPS),
                    ('patients', RangeOperators.CONTAINED_BY)
                
                ],
                condition= Q(is_archived=False) & Q(is_cancelled=False)                
        ) 
        ]

Unfortunatelly this doesn't work. The first constraint that references the Doctor works perfectly, but the second one gives me this error during migration:

return self.cursor.execute(sql, params)
psycopg2.errors.UndefinedColumn: column "patient_id" named in key does not exist

    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: column "patient_id" named in key does not exist

This has been bogging me for quite some time. Any help appreciated.