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Add common practice to default mutable argument example.
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wtfpy.md
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wtfpy.md
@ -280,6 +280,16 @@ def some_func(default_arg=[]):
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(['some_string', 'some_string'],)
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```
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A common practice to avoid bugs due to mutable arguments is to assign `None` as the default value and later check if any value is passed to the function corresponding to that argument. Examlple:
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```py
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def some_func(default_arg=None):
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if not default_arg:
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default_arg = []
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default_arg.append("some_string")
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return default_arg
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```
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## You can't change the values contained in tuples because they're immutable.. Oh really?
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@ -306,6 +316,8 @@ Quoting from https://docs.python.org/2/reference/datamodel.html
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> Immutable sequences
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An object of an immutable sequence type cannot change once it is created. (If the object contains references to other objects, these other objects may be mutable and may be changed; however, the collection of objects directly referenced by an immutable object cannot change.)
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##
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# Contributing
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All patches are Welcome! Filing an issue first before submitting a patch will be appreciated :)
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