Parse description field if return type of a function is a pydantic.BaseModel

[lienchen0526]

Parse description field if return type of a function is a pydantic.BaseModel

The usage will be like:

from pydantic import BaseModel, Field
from google.adk.tools._automatic_function_calling_util import build_function_declaration

class M(BaseModel):
  foo_field: int = Field(description = "This is a tested description")

def foo() -> M:
  pass

print(build_function_declaration(foo, variant='VERTEX_AI'))

Before this commit, the printed will be looks like:

response=Schema(example=None, pattern=None, default=None, max_length=None, min_length=None, min_properties=None, max_properties=None, any_of=None, description=None, enum=None, format=None, items=None, max_items=None, maximum=None, min_items=None, minimum=None, nullable=None, properties={'foo_field': Schema(example=None, pattern=None, default=None, max_length=None, min_length=None, min_properties=None, max_properties=None, any_of=None, description=None, enum=None, format=None, items=None, max_items=None, maximum=None, min_items=None, minimum=None, nullable=None, properties=None, property_ordering=None, required=None, title=None, type=<Type.INTEGER: 'INTEGER'>)}, property_ordering=None, required=None, title=None, type=<Type.OBJECT: 'OBJECT'>) description=None name='foo' parameters=None

which we do not track the description of foo_field of class M. After this commit, the printed will be like:

response=Schema(example=None, pattern=None, default=None, max_length=None, min_length=None, min_properties=None, max_properties=None, any_of=None, description=None, enum=None, format=None, items=None, max_items=None, maximum=None, min_items=None, minimum=None, nullable=None, properties={'foo_field': Schema(example=None, pattern=None, default=None, max_length=None, min_length=None, min_properties=None, max_properties=None, any_of=None, description='This is a tested description', enum=None, format=None, items=None, max_items=None, maximum=None, min_items=None, minimum=None, nullable=None, properties=None, property_ordering=None, required=None, title=None, type=<Type.INTEGER: 'INTEGER'>)}, property_ordering=None, required=None, title=None, type=<Type.OBJECT: 'OBJECT'>) description=None name='foo' parameters=None

TESTED=manual