doper.py remove duplicates

[JiwooChloeLee]

Pull Request Template

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

"""
from smact.dopant_prediction import doper
import pprint
pp = pprint.PrettyPrinter(indent=4)

SPECIES = (

"Zn2+",
"S2-"

)

test = doper.Doper(SPECIES, "skipspecies.json")
result = test.get_dopants(num_dopants=100)['n-type cation substitutions']
pp.pprint(result)
"""

Test Configuration:

• Python version: python 3.9.7
• Operating System: Mac Os Catalina

Reviewers

@mention individuals who you specifically want to involve in the discussion for this pull request and mention why they are needed in the discussion/why they are needed to review the pull request.

Checklist:

• [v] My code follows the style guidelines of this project
• [v] I have performed a self-review of my own code
• [v] I have commented my code, particularly in hard-to-understand areas
• [v] I have made corresponding changes to the documentation
• [v] My changes generate no new warnings
• [v] I have added tests that prove my fix is effective or that my feature works
• [v] New and existing unit tests pass locally with my changes
• [v] Any dependent changes have been merged and published in downstream modules
• [v] I have checked my code and corrected any misspellings