You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: on_call.go
    path of file: ./repos/streamdal/apps/server/vendor/github.com/PagerDuty/go-pagerduty
    
    the code of the file until where you have to start completion: package pagerduty

import (
	"context"

	"github.com/google/go-querystring/query"
)

// OnCall represents a contig
    
func (c *Client) ListOnCallsWithContext(ctx context.Context, o ListOnCallOptions) (*ListOnCallsResponse, error) {
	v, err := query.Values(o)
	if err != nil {
		return nil, err
	}

	resp, err := c.get(ctx, "/oncalls?"+v.Encode(), nil)
	if err != nil {
		return nil, err
	}

	var result ListOnCallsResponse
	if err := c.decodeJSON(resp, &result); err != nil {
		return nil, err
	}

	return &result, nil
}