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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 parse_method_configs(interface_config):
 """Creates default retry and timeout objects for each method in a gapic interface config. Args: interface_config (Mapping):
 The interface config section of the full gapic library config. For example, If the full configuration has an interface named ``google.example.v1.ExampleService`` you would pass in just that interface's configuration, for example ``gapic_config['interfaces']['google.example.v1.ExampleService']``. Returns: Mapping[str, MethodConfig]: A mapping of RPC method names to their configuration. """

    # Grab all the retry codes
    retry_codes_map = {
        name: retry_codes
        for name, retry_codes in six.iteritems(interface_config.get("retry_codes", {}))
    }

    # Grab all of the retry params
    retry_params_map = {
        name: retry_params
        for name, retry_params in six.iteritems(
            interface_config.get("retry_params", {})
        )
    }

    # Iterate through all the API methods and create a flat MethodConfig
    # instance for each one.
    method_configs = {}

    for method_name, method_params in six.iteritems(
        interface_config.get("methods", {})
    ):
        retry_params_name = method_params.get("retry_params_name")

        if retry_params_name is not None:
            retry_params = retry_params_map[retry_params_name]
            retry_ = _retry_from_retry_config(
                retry_params, retry_codes_map[method_params["retry_codes_name"]]
            )
            timeout_ = _timeout_from_retry_config(retry_params)

        # No retry config, so this is a non-retryable method.
        else:
            retry_ = None
            timeout_ = timeout.ConstantTimeout(
                method_params["timeout_millis"] / _MILLIS_PER_SECOND
            )

        method_configs[method_name] = MethodConfig(retry=retry_, timeout=timeout_)

    return method_configs