Caso insensível corresponde à sqlalchemy
from sqlalchemy import func
user = models.User.query.filter(func.lower(User.username) == func.lower("GaNyE")).first()
Disturbed Dove
from sqlalchemy import func
user = models.User.query.filter(func.lower(User.username) == func.lower("GaNyE")).first()from sqlalchemy import func
user = models.User.query.filter(func.lower(User.username) == ("GaNyE").lower()).first()