Fix error in type inference on Julia nightly

[simonster]

No description provided.

[codecov-io]

Codecov Report

Merging #24 into master will increase coverage by <.01%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master      #24      +/-   ##
==========================================
+ Coverage   92.44%   92.44%   +<.01%     
==========================================
  Files          16       16              
  Lines        2077     2079       +2     
==========================================
+ Hits         1920     1922       +2     
  Misses        157      157

Impacted Files	Coverage Δ
src/data.jl	91.6% <33.33%> (+0.02%)	⬆️

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