code: def get_guest_property_value(self, property_p):
          
          if not isinstance(property_p, basestring):
              raise TypeError("property_p can only be an instance of type basestring")
          value = self._call("getGuestPropertyValue",
                       in_p=[property_p])
          return value
docs: Reads a value from the machine's guest property store.
  
          in property_p of type str
              The name of the property to read.
  
          return value of type str
              The value of the property. If the property does not exist then this
              will be empty.
  
          raises :class:`VBoxErrorInvalidVmState`
              Machine session is not open.