Accessing a column returns Unknown type

[PerchunPak]

Why, when I access a column, it returns Unknown type instead of int?

class Schema(pa.DataFrameModel):
    example: int = pa.Field()

df = Schema.validate(pd.DataFrame({"example": 1}))
reveal_type(df["example"]) # Unknown
reveal_type(df[Schema.example]) # Unknown

This is a stupidly simple rookie question, but still I cannot find anything in docs (sorry in advance!).