I use `functools` to compute percentiles this way:

```
import functools
percentiles = tuple(functools.partial(np.percentile, q=q) for q in (75, 85, 95))

percentiles
(functools.partial(<function percentile at 0x7f91fe1e9730>, q=75),
 functools.partial(<function percentile at 0x7f91fe1e9730>, q=85),
 functools.partial(<function percentile at 0x7f91fe1e9730>, q=95))

```

so that anywhere in my code I can compute percentiles like so:

```
stat_functions =  percentiles

```

Then I want to add inter quartile to my percentile function, but adding [75-25] compute the mean instead.

```
percentiles = tuple(functools.partial(np.percentile, q=q) for q in (75, 85, 95, 75-25))

percentiles
(functools.partial(<function percentile at 0x7f91fe1e9730>, q=75),
 functools.partial(<function percentile at 0x7f91fe1e9730>, q=85),
 functools.partial(<function percentile at 0x7f91fe1e9730>, q=95),
 functools.partial(<function percentile at 0x7f91fe1e9730>, q=50))

```

My intention is to get the value of inter quartile range not the mean. How do I fix this?