Don't overflow on last bigger than end

[devbugging]

Description

When running locally if fewer blocks were created than the last flag specified then it overflowed the range.

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For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov-commenter]

Codecov Report

Merging #392 (c8ef2ff) into master (ff1f8b1) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #392   +/-   ##
=======================================
  Coverage   55.33%   55.33%           
=======================================
  Files          36       36           
  Lines        1874     1874           
=======================================
  Hits         1037     1037           
  Misses        707      707           
  Partials      130      130           

Flag	Coverage Δ
unittests	55.33% <ø> (ø)

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