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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _AddCredentialConfiguration( self, path_spec, credential_type, credential_data):
 """Adds a credential configuration. Args: path_spec (dfvfs.PathSpec):
 path specification. credential_type (str):
 credential type. credential_data (bytes):
 credential data. """

    credential_configuration = configurations.CredentialConfiguration(
        credential_data=credential_data, credential_type=credential_type,
        path_spec=path_spec)

    self._credential_configurations.append(credential_configuration)