func DeleteDiagram(fileName string) error {
	err := os.Remove(fileName)
	if isError(err) {
		return err
	}
	return nil
}
DeleteDiagram deletes a diagram.
package io
import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
)
func ReadFile(input string) []byte {
	b, err := ioutil.ReadFile(input)
	if err != nil {
		return nil
	}
	return b
}
func SaveFile(fileName string, output string, data string) (*os.File, error) {
	var file *os.File
	cwd, err := filepath.Abs(filepath.Dir(""))
	if err != nil {
		log.Fatal(err)
	}
	filePath := cwd + output
	if _, err := os.Stat(filePath); os.IsNotExist(err) {
		os.Mkdir(filePath, os.ModePerm)
	}
	file, err = os.Create(filepath.Join(filePath, fileName))
	if isError(err) {
		return nil, err
	}
	file, err = os.OpenFile(filepath.Join(filePath, fileName), os.O_RDWR, 0644)
	if isError(err) {
		return nil, err
	}
	defer file.Close()
	_, err = file.WriteString(data)
	if isError(err) {
		return nil, err
	}
	return file, nil
}