Returns true if this is a 64 bit process.

def Is64bit(self):
    """Returns true if this is a 64 bit process."""
    if "64" not in platform.machine():
      return False
    iswow64 = ctypes.c_bool(False)
    if IsWow64Process is None:
      return False
    if not IsWow64Process(self.h_process, ctypes.byref(iswow64)):
      raise process_error.ProcessError("Error while calling IsWow64Process.")
    return not iswow64.value