The default value of locals for exec should be None instead of {}

[welfare520]

langchain-experimental/libs/experimental/langchain_experimental/utilities/python.py

Line 48 in 7177f46

locals: Optional[Dict],

This code will fail, with an error: NameError("name 're' is not defined")
code = """
import re

def return_parts(value):
parts = re.split(r'[,.]', value)
return parts

print(return_parts("100,36"))
"""
python_repl = PythonREPL()
python_repl.run(code)

This is because the default value {} of locals overrides the imported packages. Therefore the default value of locals in the class PythonREPL should be None instead of {}