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: user_report.go
    path of file: ./repos/client/go/service
    
    the code of the file until where you have to start completion: // Copyright 2019 Keybase, Inc. All rights reserved. Use of
// this source code is governed by the included BSD license.

package service

import (
	"encoding/json"
	"fmt"

	"github.com/keybase/client/go/chat"
	"github.com/keybase/client/go/chat/types"
	"github.com/keybase/client/go/kbun"

	"github.com/keybase/client/go/libkb"
	"github.com/keybase/client/go/protocol/chat1"
	keybase1 "github.com/keybase/client/go/protocol/keybase1"
	"golang.org/x/net/context"
)

// pullTranscript uses chat transcript functions to pull transcript and encode
// it to postArgs.
func pullTranscript(mctx libkb.MetaContext, postArgs libkb.HTTPArgs, convSource types.ConversationSource,
	convID chat1.ConvIDStr, usernames []kbun.NormalizedUsername) (err error) {

	config := chat.PullTranscriptConfigDefault()
	transcript, err := 
    
func (h *UserHandler) ReportUser(ctx context.Context, arg keybase1.ReportUserArg) (err error) {
	mctx := libkb.NewMetaContext(ctx, h.G()).WithLogTag("REPORT")
	defer mctx.Trace(fmt.Sprintf(
		"UserHandler#ReportUser(username=%q,transcript=%t,convId=%v)",
		arg.Username, arg.IncludeTranscript, arg.ConvID),
		&err)()

	postArgs := libkb.HTTPArgs{
		"username": libkb.S{Val: arg.Username},
		"reason":   libkb.S{Val: arg.Reason},
		"comment":  libkb.S{Val: arg.Comment},
	}
	if arg.ConvID != nil {
		postArgs["conv_id"] = libkb.S{Val: *arg.ConvID}
	}
	if arg.IncludeTranscript && arg.ConvID != nil {
		convID := *arg.ConvID
		// Pull transcripts with messages from curent user and the reported user.
		usernames := []kbun.NormalizedUsername{
			kbun.NewNormalizedUsername(arg.Username),
			mctx.CurrentUsername(),
		}
		err = pullTranscript(mctx, postArgs, h.ChatG().ConvSource, chat1.ConvIDStr(convID), usernames)
		if err != nil {
			// This is not a failure of entire RPC, just warn about the error.
			// Report can still go through without the transcript.
			mctx.Warning("Could not load conversation transcript: %s", err)
		}
	}

	apiArg := libkb.APIArg{
		Endpoint:    "report/conversation",
		SessionType: libkb.APISessionTypeREQUIRED,
		Args:        postArgs,
	}
	_, err = mctx.G().API.Post(mctx, apiArg)
	return err
}