Possible exception during validation of IPAddressField

[Stranger6667]

I faced with not expected behaviour of IPAddress field during validation certain types of input.

Checklist

• I have verified that that issue exists against the master branch of Django REST framework.
• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• This is not a usage question. (Those should be directed to the discussion group instead.)
• This cannot be dealt with as a third party library. (We prefer new functionality to be in the form of third party libraries where possible.)
• I have reduced the issue to the simplest possible case.
• I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

1. Create a serializer with IPAddressField
2. Pass not iterable object as input for the serializer. E.g. integer.

Expected behavior

Validation error with usual text:
['Enter a valid IPv4 or IPv6 address.']

Actual behavior

Exception:

rest_framework/fields.py:701: in run_validation
    return super(CharField, self).run_validation(data)
rest_framework/fields.py:487: in run_validation
    value = self.to_internal_value(data)
rest_framework/fields.py:807: in to_internal_value
    if data and ':' in data:
E   TypeError: argument of type 'int' is not iterable

[lovelydinosaur]

Yup, looks valid, given your test case.