code: function exportTypeScriptDeclarations (classes) {
  
      const file = './ccxt.d.ts'
      const regex = /(?:    export class [^\s]+ extends [^\s]+ \{\}[\r]?[\n])+/
      const replacement = Object.keys (classes).map (className => {
          const baseClass = classes[className]
          return '    export class ' + className + ' extends ' + baseClass + " {}"
      }).join ("\n") + "\n"
  
      replaceInFile (file, regex, replacement)
  }
docs: -----------------------------------------------------------------------------