Wrong data types in documentation for get_order_book, ticker, incremantal_ticker.{instrument_name} and ticker.{instrument_name}.{interval}

[psollberger]

There seems to be a discrepancy between the documentation and what the API actually returns.

According to the documentation for:

• public/get_order_book
• public/ticker
• incremental_ticker.{instrument_name}
• ticker.{instrument_name}.{interval}

The data type for underlying_index is a number, but it seems (at least for public/get_order_book) that the field is actually a string.

In which of those requests the documentation is wrong and in which it isn't?