Warn when Redefining functions

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examples/linters/redef.py

sum = 42

def len(thing):
    print(f"Use {thing}.__len__() instead!")

len("abc")

pylint redef.py

************* Module redef
redef.py:1:0: C0111: Missing module docstring (missing-docstring)
redef.py:2:0: W0622: Redefining built-in 'sum' (redefined-builtin)
redef.py:4:0: W0622: Redefining built-in 'len' (redefined-builtin)
redef.py:2:0: C0103: Constant name "sum" doesn't conform to UPPER_CASE naming style (invalid-name)
redef.py:4:0: C0111: Missing function docstring (missing-docstring)

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Your code has been rated at -2.50/10 (previous run: -2.50/10, +0.00)