old_contents: # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  # implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from __future__ import absolute_import, division, print_function
  
  from cryptography.hazmat.bindings.utils import (
      build_ffi, binding_available
  )
  
  
  class Binding(object):
      """
      CommonCrypto API wrapper.
      """
      _module_prefix = "cryptography.hazmat.bindings.commoncrypto."
      _modules = [
          "common_digest",
      ]
  
      ffi = None
      lib = None
  
      def __init__(self):
          self._ensure_ffi_initialized()
  
      @classmethod
      def _ensure_ffi_initialized(cls):
          if cls.ffi is not None and cls.lib is not None:
              return
  
          cls.ffi, cls.lib = build_ffi(cls._module_prefix, cls._modules,
                                       "", "", [])
  
      @classmethod
      def is_available(cls):
          return binding_available(cls._ensure_ffi_initialized)
  
new_contents: # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  # implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from __future__ import absolute_import, division, print_function
  
  import sys
  
  from cryptography.hazmat.bindings.utils import build_ffi
  
  
  class Binding(object):
      """
      CommonCrypto API wrapper.
      """
      _module_prefix = "cryptography.hazmat.bindings.commoncrypto."
      _modules = [
          "common_digest",
      ]
  
      ffi = None
      lib = None
  
      def __init__(self):
          self._ensure_ffi_initialized()
  
      @classmethod
      def _ensure_ffi_initialized(cls):
          if cls.ffi is not None and cls.lib is not None:
              return
  
          cls.ffi, cls.lib = build_ffi(cls._module_prefix, cls._modules,
                                       "", "", [])
  
      @classmethod
      def is_available(cls):
          return sys.platform == "darwin"
  
subject: refactor commoncrypto's is_available to check platform for now