Cannot handle negative numbers?

[afzalmushtaque]

'$'+ballpark.business(100000)

Out[23]: '$100K'

'$'+ballpark.business(-100000)

Traceback (most recent call last):
File "C:\Python\Python36\lib\site-packages\IPython\core\interactiveshell.py", line 2963, in run_code
exec(code_obj, self.user_global_ns, self.user_ns)
File "", line 1, in
'$'+ballpark.business(-100000)
File "C:\Python\Python36\lib\site-packages\ballpark\utils.py", line 90, in unwrapped_function
results = fn(values, *vargs, **kwargs)
File "C:\Python\Python36\lib\site-packages\ballpark\notation.py", line 130, in business
exponent = order(reference)
File "C:\Python\Python36\lib\site-packages\ballpark\notation.py", line 18, in order
power = log(repel(value), base)
ValueError: math domain error