fix: check duplicates schemas when loading swagger

[Marwen94]

Closes #156

[codecov]

Codecov Report

Merging #157 (45dd535) into master (a29b4f9) will increase coverage by 0.12%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #157      +/-   ##
==========================================
+ Coverage   95.97%   96.09%   +0.12%     
==========================================
  Files          18       18              
  Lines         547      564      +17     
  Branches      103      109       +6     
==========================================
+ Hits          525      542      +17     
  Misses         12       12              
  Partials       10       10              

Impacted Files	Coverage Δ
openapi_spec_validator/handlers/compat.py	90.90% <100.00%> (+30.90%)	⬆️
openapi_spec_validator/handlers/file.py	100.00% <100.00%> (ø)

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[Marwen94]

@p1c2u could you please have a look at this PR ?

[p1c2u]

Looks good. Just wondering how this affects the performance.

[Marwen94]

Looks good. Just wondering how this affects the performance.

I don't think this influences a lot the performance since it only adds an o(n) complexity where n is the number of schema in a given swagger. Imho n in a real world context is in [1, 100].

We can set the duplicate check optional also, what do you think ?