text: #!/usr/bin/env python3
  #
  # MIT License
  #
  # Copyright (c) 2021 Konychev Valera
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the "Software"), to deal
  # in the Software without restriction, including without limitation the rights
  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  # copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in all
  # copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  # SOFTWARE.
  
  import os
  import platform
  
  OS = platform.system()
  
  def isLinux():
      return OS == 'Linux'
  
  def isMacOsX():
      return OS == 'Darwin'
  
  def isWin():
      return OS == 'Windows'
  
  def execForOs(linux=None, mac=None, win=None):
      if isLinux():
          if linux is None:
              raise 'Where is no Linux hadler'
          linux()
      elif isMacOsX():
          if mac is None:
              raise 'Where is no Mac OS X hadler'
          mac()
      elif isWin():
          if win is None:
              raise 'Where is no Win hadler'
          win()
      else:
          raise 'Unknown OS'
  
  def getForOs(linux=None, mac=None, win=None):
      if isLinux():
          return linux
      elif isMacOsX():
          return mac
      elif isWin():
          return win
      else:
          raise 'Unknown OS'
  
  def appendPath(newPath):
      def appendNixPath():
          return
      def appendWinPath():
          os.system(f'setx path "%path%;{newPath}"')
  
      execForOs(
          linux = appendNixPath,
          mac = appendNixPath,
          win = appendWinPath
      )
  
  