<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _make_env_vars(self, function):
 """Returns the environment variables configuration for this function Parameters function : samcli.commands.local.lib.provider.Function Lambda function to generate the configuration for Returns ------- samcli.local.lambdafn.env_vars.EnvironmentVariables Environment variable configuration for this function Raises ------ samcli.commands.local.lib.exceptions.OverridesNotWellDefinedError If the environment dict is in the wrong format to process environment vars """


        name = function.name

        variables = None
        if function.environment and isinstance(function.environment, dict) and "Variables" in function.environment:
            variables = function.environment["Variables"]
        else:
            LOG.debug("No environment variables found for function '%s'", name)

        # This could either be in standard format, or a CloudFormation parameter file format.
        #
        # Standard format is {FunctionName: {key:value}, FunctionName: {key:value}}
        # CloudFormation parameter file is {"Parameters": {key:value}}

        for env_var_value in self.env_vars_values.values():
            if not isinstance(env_var_value, dict):
                reason = """
                            Environment variables must be in either CloudFormation parameter file
                            format or in {FunctionName: {key:value}} JSON pairs
                            """
                LOG.debug(reason)
                raise OverridesNotWellDefinedError(reason)

        if "Parameters" in self.env_vars_values:
            LOG.debug("Environment variables overrides data is in CloudFormation parameter file format")
            # CloudFormation parameter file format
            overrides = self.env_vars_values["Parameters"]
        else:
            # Standard format
            LOG.debug("Environment variables overrides data is standard format")
            overrides = self.env_vars_values.get(name, None)

        shell_env = os.environ
        aws_creds = self.get_aws_creds()

        return EnvironmentVariables(function.memory,
                                    function.timeout,
                                    function.handler,
                                    variables=variables,
                                    shell_env_values=shell_env,
                                    override_values=overrides,
                                    aws_creds=aws_creds)