`from schematics.models import Model
from schematics.types import StringType, FloatType

class schema(Model):
f1 = StringType(choices=['a'])
f2 = FloatType()

sample ={'f1': 'b', 'f2': 'x'}
instance = schema (sample)
instance.validate`

The exception only shows the float error without even initialixing the instance. How do I collect all errors according to documentation?