How to get custom field of customer doc type via APIs

Frappe is returning back just default field values. It’s not returning custom fields created by me in customer doc type. How to get those custom fields also??

In my script I am using below code,

$result = $client->get(
					"Customer",
					"Puneet Saharey"
				);
	//var_dump($result);
	echo json_encode($result);

Result I am getting from frappe,

"errorno":0,"error":null,"body":{"data":{"naming_series":"CUST-","creation":"2017-07-12 19:04:24.446863","doctype":"Customer","disabled":0,"accounts":[],"owner":"Administrator","modified_by":"Administrator","customer_type":"Individual","customer_name":"Puneet Saharey","credit_days":0,"docstatus":0,"territory":"India","default_commission_rate":0,"language":"en-US","credit_limit":0,"name":"Puneet Saharey - 1","idx":1,"credit_days_based_on":"","customer_group":"Individual","modified":"2017-07-12 19:04:28.995813","is_frozen":0,"sales_team":[]}},"header":{"url":"http:\/\/139.59.77.215\/api\/resource\/Customer\/Puneet Saharey - 1","content_type":"application\/json","http_code":200,"header_size":465,"request_size":240,"filetime":-1,"ssl_verify_result":0,"redirect_count":0,"total_time":0.505116,"namelookup_time":2.9e-5,"connect_time":0.239425,"pretransfer_time":0.239428,"size_upload":0,"size_download":518,"speed_download":1025,"speed_upload":0,"download_content_length":518,"upload_content_length":0,"starttransfer_time":0.505027,"redirect_time":0,"certinfo":[],"primary_ip":"139.59.77.215","redirect_url":""},"is_auth":true}

client.get method returns all the fields (cutsom and standard), can you please check again.

client.get is same as $client->get , so it should returns all the fields (custom and standard).

I have this $client->get in my FrappeClient file as below.

public function get(
			$doctype
			,$key
		){
			$this->_auth_check();
			return $this->_curl(
				'GET'
				, array(
					'doctype' => $doctype
					,'data' => $key
					)
				);
		}

Can somebody help here- Really stuck!!!