<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def SetupVars(self):
 """Set up some vars for the directories we use."""

    # Python paths chosen to match appveyor:
    # http://www.appveyor.com/docs/installed-software#python

    self.python_dir_64 = args.python64_dir
    self.python_dir_32 = args.python32_dir

    self.virtualenv_bin64 = os.path.join(self.python_dir_64,
                                         r"Scripts\virtualenv.exe")
    self.virtualenv_bin32 = os.path.join(self.python_dir_32,
                                         r"Scripts\virtualenv.exe")

    if args.virtualenv_64bit:
      self.virtualenv64 = args.virtualenv_64bit
    else:
      self.virtualenv64 = os.path.join(args.build_dir, "python_64")
    if args.virtualenv_32bit:
      self.virtualenv32 = args.virtualenv_32bit
    else:
      self.virtualenv32 = os.path.join(args.build_dir, "python_32")

    self.grr_client_build64 = os.path.join(self.virtualenv64,
                                           r"Scripts\grr_client_build.exe")
    self.grr_client_build32 = os.path.join(self.virtualenv32,
                                           r"Scripts\grr_client_build.exe")
    self.pip64 = os.path.join(self.virtualenv64, r"Scripts\pip.exe")
    self.pip32 = os.path.join(self.virtualenv32, r"Scripts\pip.exe")

    self.virtualenv_python64 = os.path.join(self.virtualenv64,
                                            r"Scripts\python.exe")
    self.virtualenv_python32 = os.path.join(self.virtualenv32,
                                            r"Scripts\python.exe")

    self.git = r"C:\Program Files\Git\bin\git.exe"

    self.install_path = r"C:\Windows\System32\GRR"
    self.service_name = "GRR Monitor"

    self.expect_service_running = args.expect_service_running