minor docstring and lint fix

[yawen-d]

No description provided.

[AdamGleave]

LGTM. Think a black upgrade caused it to complain about powers when it didn't previously, thanks for the fix.

[codecov]

Codecov Report

Merging #53 (8ed787f) into master (77cf796) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #53   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           24        24           
  Lines          704       704           
=========================================
  Hits           704       704           

Impacted Files	Coverage Δ
src/seals/mujoco.py	100.00% <ø> (ø)
src/seals/diagnostics/parabola.py	100.00% <100.00%> (ø)

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