Data validation contracts with Pandera for pipeline reliability

                  import pandera as pa
from pandera.typing import Series

class ChurnTrainingSchema(pa.DataFrameModel):
    customer_id: Series[int] = pa.Field(unique=True)
    age: Series[int] = pa.Field(ge=18, le=100)
    income: Series[float] = pa.Field(ge=0)
    country: Series[str]
    churned: Series[int] = pa.Field(isin=[0, 1])

validated_df = ChurnTrainingSchema.validate(df, lazy=True)
print(validated_df.head())