At the moment we can keep a single code path when using IntParameter, but we have to make a special hyperopt case for CategoricalParameter/DecimalParameter. Range property solves this.
Exception is triggered by backtesting 20210301-20210501 range with BAKE/USDT pair (binance). Pair data starts on 2021-04-30 12:00:00 and after adjusting for startup candles pair dataframe is empty.
Solution: Since there are other pairs with enough data - skip pairs with no data and issue a warning.
Exception:
```
Traceback (most recent call last):
File "/home/rk/src/freqtrade/freqtrade/main.py", line 37, in main
return_code = args['func'](args)
File "/home/rk/src/freqtrade/freqtrade/commands/optimize_commands.py", line 53, in start_backtesting
backtesting.start()
File "/home/rk/src/freqtrade/freqtrade/optimize/backtesting.py", line 502, in start
min_date, max_date = self.backtest_one_strategy(strat, data, timerange)
File "/home/rk/src/freqtrade/freqtrade/optimize/backtesting.py", line 474, in backtest_one_strategy
results = self.backtest(
File "/home/rk/src/freqtrade/freqtrade/optimize/backtesting.py", line 365, in backtest
data: Dict = self._get_ohlcv_as_lists(processed)
File "/home/rk/src/freqtrade/freqtrade/optimize/backtesting.py", line 199, in _get_ohlcv_as_lists
pair_data.loc[:, 'buy'] = 0 # cleanup from previous run
File "/home/rk/src/freqtrade/venv/lib/python3.9/site-packages/pandas/core/indexing.py", line 692, in __setitem__
iloc._setitem_with_indexer(indexer, value, self.name)
File "/home/rk/src/freqtrade/venv/lib/python3.9/site-packages/pandas/core/indexing.py", line 1587, in _setitem_with_indexer
raise ValueError(
ValueError: cannot set a frame with no defined index and a scalar
```
* Fix custom_sell() example to use rsi from last-available instead of trade-open candle, add a pointer to "Dataframe access" section for more info.
* Simplify "Custom stoploss using an indicator from dataframe example" greatly, add a pointer to "Dataframe access" section for more info.
This parameter allows us to customize a number of days we would like to download for new pairs only. This allows us to achieve efficient data update, downloading all data for new pairs and only missing data for existing pairs. To do that use `freqtrade download-data --new-pairs-days=3650` (not specifying `--days` or `--timerange` causes freqtrade to download only missing data for existing pairs).
* Split Parameter into IntParameter/FloatParameter/CategoricalParameter.
* Rename IHyperStrategy to HyperStrategyMixin and use it as mixin.
* --hyperopt parameter is now optional if strategy uses HyperStrategyMixin.
* Use OperationalException() instead of asserts.
Rokas Kupstys