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: Convert.go
    path of file: ./repos/tegola/vendor/github.com/go-spatial/proj
    
    the code of the file until where you have to start completion: // Copyright (C) 2018, Michael P. Gerlek (Flaxen Consulting)
//
// Portions of this code were derived from the PROJ.4 software
// In keeping with the terms of the PROJ.4 project, this software
// is provided under the MIT-style license in `LICENSE.md` and may
// additionally be subject to the copyrights of the PROJ.4 authors.

package proj

import (
	"fmt"
	"sync"

	"github.com/go-spatial/proj/core"
	"github.com/go-spatial/proj/support"

	// need to pull in the operations table entries
	_ "github.com/go-spatial/proj/operations"

    
func (conv *conversion) convert(input []float64) ([]float64, error) {

	if conv == nil || conv.converter == nil {
		return nil, fmt.Errorf("conversion not initialized")
	}

	if len(input)%2 != 0 {
		return nil, fmt.Errorf("input array of lon/lat values must be an even number")
	}

	output := make([]float64, len(input))

	lp := &core.CoordLP{}

	for i := 0; i < len(input); i += 2 {
		lp.Lam = support.DDToR(input[i])
		lp.Phi = support.DDToR(input[i+1])

		xy, err := conv.converter.Forward(lp)
		if err != nil {
			return nil, err
		}

		output[i] = xy.X
		output[i+1] = xy.Y
	}

	return output, nil
}