pylint/checkers/base.py
def visit_dict(self, node):
        """check duplicate key in dictionary"""
        keys = set()
        for k, _ in node.items:
            if isinstance(k, astroid.Const):
                key = k.value
                if key in keys:
                    self.add_message("duplicate-key", node=node, args=key)
                keys.add(key)
def visit_dict(self, node):
        """check duplicate key in dictionary"""
        keys = set()
        for k, _ in node.items:
            if isinstance(k, astroid.Const):
                key = k.value
                if key in keys:
                    self.add_message("duplicate-key", node=node, args=key)
                keys.add(key)
check duplicate key in dictionary