deletions to make valid parentheses python

[abed42]

• [ ] PR's title includes the challenge's name and language
• [x] PR has short and clear description of the challenge
• [x] PR has appropriate labels and milestones for easy identification
• [x] PR it is assigned to the owner
• [x] reviewers are assigned
• [x] the PR contributes only one focused change
• [x] the branch is up to date with main/master
• [x] the code works when pulled and run locally
• [ ] all conflicts are resolved (if any)
• [x] It is linked to an issue in the appropriate column of the project board
• [ ] feedback is addressed (if any, and if it is appropriate feedback.)

README Documentation

• [x] The solution is documented in /src/README.md
• [x] The markdown source is formatted
• [x] Spelling and grammar is correct in all text
• [x] The markdown looks correct when you preview the file
• [x] All links and images work
• [ ] The README documents the solution's behavior, strategy(ies) and implementation(s)
• [x] There are use cases in code blocks to illustrate the function's behavior

Python Files

• [x] There is a module header
• [x] There is a module docstring
• [x] File names are in snake_case
• [x] Test files are named test_<module_name>.py

Function Docstring

• [x] Behavior description
• [x] Parameter description
• [x] Return value description
• [ ] Include any assumptions
• [ ] Include 3 or more (passing!) doctests
• [ ] Include 1-2 use cases (if necessary)

Function Implementation

• [ ] The solution is not is not copied from djeada
• [ ] The code is auto-formatted
• [ ] The code has no (reasonable) linting mistakes
• [ ] Variables are named with snake_case
• [ ] The function has a clear and helpful name
• [ ] The file's name matches the function name
• [ ] The code follows the strategy as simply as possible
• [ ] Variable names are clear and helpful
• [ ] Comments explain the strategy (if necessary)
• [ ] There are type annotations
• [ ] (challenge) The code includes defensive assertions

Unit Test Suite

• [x] The test class has a helpful name in PascalCase
• [x] The test class has a docstring
• Each unit test has
  • [ ] A helpful name
  • [ ] A clear docstring
  • [ ] Only one assertion
• [x] All tests pass
• [ ] There are tests for defensive assertions
• [ ] There are tests for boundary cases
• [ ] Test suite includes black-box and glass-box tests