get_ema_dollar_imbalance_bars returns empty dataframe

[eugencuic]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. use a dataset that create a pandas frame when generating tick_bars
2. use same dataset as above and create get_ema_dollar_imbalance_bars
3. the function returns a tuple instead of a dataframe

Expected behavior
To get the same DataFrame as with standard data strucutres

Desktop (please complete the following information):

• OS: Windows
• Version: 0.15.3

[ahmedyounis]

This is also a problem for get_ema_dollar_run_bars, get_const_dollar_run_bars,get_ema_volume_run_bars.
The functions return an empty DataFrame.

Ass you can see, a Tuple is generated by the functions and not a DataFrame.

[eugencuic]

the output is a tuple (x,y) and you get the dataframe by calling the first element of the tuple:
tuple[0]
@ahmedyounis

[ahmedyounis]

Thanks @eugencuic 👍