Fix non working examples

[iduartgomez]

There are a couple of examples that won't work because the necessary data is not available:

• file_read
• parquet_column_read

We should either provide a small sample with the tests or change the tests with some fake data so those examples can be executed.

[rajasekarv]

I will add the sample data today for both txt and parquet formats

[AmbitionXiang]

Hi, I didn't find the data you added. I wonder where it is. Thank you.