Cast CamelCase to "underscore_case"

main_re.py

import re

def _camel_to_underscore_case(name):
    """
    Translate 'CamelCaseNames' to 'camel_case_names'.
    """
    camelcase_boundry = '((?<=[a-z])[A-Z])'
    return re.sub(camelcase_boundry, '_\\1', name).lower()

def camel_to_underscore_case(obj, deep=True):
    if isinstance(obj, dict):
        return dict((_camel_to_underscore_case(k),
                     camel_to_underscore_case(v, deep) if deep else v)
                    for k,v in obj.iteritems())
    elif deep and isinstance(obj, list):
        return map(lambda x: camel_to_underscore_case(x, deep), obj)
    else:
        return obj

if __name__ == "__main__":

    import unittest

    class TestCamelToUnderscore(unittest.TestCase):

        def setUp(self):
            self.input = {'object': [
                                    {"IsCustomer": True, "OBID": 12345},
                                    {"isCustomer": True, "obid": 12345},
                                    {"is_customer": True, "obid": 12345},
                                    {"isCustomer": True, "Obid": 12345},
                                    {"obj": {"isCustomer": True, "Obid": 12345}}
            ]}

        def test_conversion(self):
            
            output = camel_to_underscore_case(self.input)

            camelcased = {"is_customer": True, "obid": 12345}
            expected = {'object': [camelcased] * 4 + [{"obj": camelcased}]}
            
            self.assertDictEqual(expected, output)

    unittest.main()