Find duplicates python exercise

duplicates.py

"""
Write functions that:
a. detects if an array/slice has duplicates
b. detects what the duplicates are
c. counts the duplicates
You may tackle these in any order 
You may alter the signatures of the skeletons to meet your needs
"""
from typing import List, Mapping, TypeVar, Iterable
import pytest


V = TypeVar('V')


def has_duplicates(input: List[V]) -> bool:
    """
    a. detects if an array/slice has duplicates
    """
    pass


def get_duplicates(input: List[V]) -> Iterable:
    """
    b. detects what the duplicates are
    """
    pass


def get_duplicate_counts(input: List[V]) -> Mapping[V, int]:
    """
    c. counts the duplicates
    """
    pass


@pytest.mark.parametrize(
    "a,expected",
    [
        pytest.param(
            [0,1], False
        ),
        pytest.param(
            [1, 0], False
        ),
        pytest.param(
            [1, 0, 0], True
        ),

    ],
)
def test_has_duplicates(a, expected):
    assert has_duplicates(a) == expected


def test_get_duplicates_with_dups():
    assert get_duplicates([1,1,2]) == [1]

tox.ini

[tox]
envlist = py38
skipsdist = True

[src]
files = duplicates.py

[testenv]
deps = mypy >= v0.900
       pytest
       pylint
       # -r requirements.txt
commands =
    python -m mypy --ignore-missing-imports --show-error-codes --warn-unreachable --config-file=tox.ini {[src]files}
    # python -m pylint {[src]files}
    pytest {[src]files}

[mypy]

[mypy-google.*]
ignore_missing_imports = True