# syntax
# def <function name>(<positional argument1>, <pos argument 2>, ..., <keyword argument1>=<default value>, <keyword argument2>=<default value>, ...):
#     ...

# optional syntax (documentation, linter hints)
# def <func name>(<arg>:<type>, <keyarg>:<type>=<default>):
#     ...

def greet_from_list(greeting: str, name_list: list=None):
    #                                      ^^^^^^^^^
    # watchout for mutable types as default values ie don't do name_list=[] !!
    # instead do: name_list=None
    # and then check if user user has provided a value:
    if name_list is None:
        name_list = ["World"]

    for name in name_list:
        print(f"{greeting} {name}!")

if '__main__' == __name__:
    greet_from_list("Hi", ["Bob", "Jack"])
    # >>> Hi Bob!
    # >>> Hi Jack!

    # positional parameters can also be set "as" keyword parameters
    greet_from_list(greeting="Hello")
    # >>> Hello World!