Add bounds checking to list

[simonbyrne]

Fixes #417.

[codecov]

Codecov Report

Merging #443 (57686bf) into master (65cd62e) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #443      +/-   ##
==========================================
+ Coverage   77.97%   78.02%   +0.05%     
==========================================
  Files          23       23              
  Lines        1607     1611       +4     
==========================================
+ Hits         1253     1257       +4     
  Misses        354      354              

Impacted Files	Coverage Δ
src/methods.jl	68.16% <100.00%> (+0.44%)	⬆️

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