def __enter__(self):
<EOL>self._template_dict = self._get_template_data(self._template_file)<EOL>self._function_provider = SamFunctionProvider(self._template_dict, self.parameter_overrides)<EOL>self._env_vars_value = self._get_env_vars_value(self._env_vars_file)<EOL>self._log_file_handle = self._setup_log_file(self._log_file)<EOL>self._debug_context = self._get_debug_context(self._debug_port,<EOL>self._debug_args,<EOL>self._debugger_path)<EOL>self._container_manager = self._get_container_manager(self._docker_network,<EOL>self._skip_pull_image)<EOL>if not self._container_manager.is_docker_reachable:<EOL><INDENT>raise InvokeContextException("<STR_LIT>")<EOL><DEDENT>return self<EOL>
Performs some basic checks and returns itself when everything is ready to invoke a Lambda function.

:returns InvokeContext: Returns this object