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: viper_go1_15.go
    path of file: ./repos/fabio/vendor/github.com/spf13/viper
    
    the code of the file until where you have to start completion: //go:build !go1.16 || !finder
// +build !go1.16 !finder

package viper

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/spf13/afero"
)

// Search all configPaths for any config file.
// Returns the first path that exists (and is a config file).
func (v *Viper) findConfigFile() (string, error) {
	v.logger.Info("searching for config in paths", "paths", v.configPaths)

	for _, cp := range v.configP
    
func (v *Viper) searchInPath(in string) (filename string) {
	v.logger.Debug("searching for config in path", "path", in)
	for _, ext := range SupportedExts {
		v.logger.Debug("checking if file exists", "file", filepath.Join(in, v.configName+"."+ext))
		if b, _ := exists(v.fs, filepath.Join(in, v.configName+"."+ext)); b {
			v.logger.Debug("found file", "file", filepath.Join(in, v.configName+"."+ext))
			return filepath.Join(in, v.configName+"."+ext)
		}
	}

	if v.configType != "" {
		if b, _ := exists(v.fs, filepath.Join(in, v.configName)); b {
			return filepath.Join(in, v.configName)
		}
	}

	return ""
}