returnTradeHistory in poloniex always returns empty list

I'm using the python wrapper provided by poloniex: wrapper

The method I'm trying to run now is:

def returnTradeHistory(self,currencyPair):
    return self.api_query('returnTradeHistory',{"currencyPair":currencyPair})

But the method .returnTradeHistory() always returns an empty list, even if I have already made a trade, using that coin. The other methods are working as expected, even those that also need the private API ( return balances for example ).

Here is a print of the output:

And here is a print of my trade history:

What am I missing here?

Well, reading the documentation once more I saw this:

Returns your trade history for a given market, specified by the currencyPair POST parameter. You may specify "all" as the currencyPair to receive your trade history for all markets. You may optionally specify a range via start and/or end POST parameters, given in UNIX timestamp format; if you do not specify a range, it will be limited to one day.

So, sorry for the dumb question.