code: def test_sizes(self):
      dll = CDLL(_ctypes_test.__file__)
      for i in range(1, 11):
          fields = [("f%d" % f, c_char) for f in range(1, i + 1)]
  
          class S(Structure):
              _fields_ = fields
  
          f = getattr(dll, "TestSize%d" % i)
          f.restype = S
          res = f()
          for i, f in enumerate(fields):
              value = getattr(res, f[0])
              expected = chr(ord("a") + i)
              self.assertEquals(value, expected)
  
imports: from ctypes import *
  from ctypes.test import requires
  import unittest, sys
  from test import test_support
  import _ctypes_test
label_desc: Use image node_id 1 for calling the ReturnStructSizesTestCase obj's underlying member method code with example usage: obj.test_sizes() without return types