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Solve the following problem using Python, implementing the functions described below, one line at a time
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<USER_TASK:>
Description:
 def GetDecrypter(cls, encryption_method, **kwargs):
 """Retrieves the decrypter object for a specific encryption method. Args: encryption_method (str):
 encryption method identifier. kwargs (dict):
 keyword arguments depending on the decrypter. Returns: Decrypter: decrypter or None if the encryption method does not exists. Raises: CredentialError: if the necessary credentials are missing. """

    encryption_method = encryption_method.lower()
    decrypter = cls._decrypters.get(encryption_method, None)
    if not decrypter:
      return None

    return decrypter(**kwargs)