#2115 Boolean operator not implemented

[valentinsulzer]

Description

Fixes #2115

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ flake8
• All tests pass: $ python run-tests.py --unit
• The documentation builds: $ cd docs and then $ make clean; make html

You can run all three at once, using $ python run-tests.py --quick.

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Merging #2141 (fecbd28) into develop (b240796) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #2141   +/-   ##
========================================
  Coverage    99.38%   99.38%           
========================================
  Files          355      355           
  Lines        19302    19308    +6     
========================================
+ Hits         19183    19189    +6     
  Misses         119      119           

Impacted Files	Coverage Δ
pybamm/expression_tree/functions.py	100.00% <100.00%> (ø)
pybamm/expression_tree/symbol.py	98.55% <100.00%> (+<0.01%)	⬆️
pybamm/models/base_model.py	99.26% <100.00%> (ø)
pybamm/models/submodels/particle/base_particle.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b240796...fecbd28. Read the comment docs.

[rtimms]

thanks @tinosulzer looks good!