code: def _getOverlay(self, readDataInstance, sectionHdrsInstance):
          
          if readDataInstance is not None and sectionHdrsInstance is not None:            
              # adjust the offset in readDataInstance to the RawOffset + RawSize of the last section
              try:
                  offset = sectionHdrsInstance[-1].pointerToRawData.value + sectionHdrsInstance[-1].sizeOfRawData.value
                  readDataInstance.setOffset(offset)
              except excep.WrongOffsetValueException:
                  if self._verbose:
                      print "It seems that the file has no overlay data."
          else:
              raise excep.InstanceErrorException("ReadData instance or SectionHeaders instance not specified.")
              
          return readDataInstance.data[readDataInstance.offset:]
docs: Returns the overlay data from the PE file.
          
          @type readDataInstance: L{ReadData}
          @param readDataInstance: A L{ReadData} instance containing the PE file data.
          
          @type sectionHdrsInstance: L{SectionHeaders}
          @param sectionHdrsInstance: A L{SectionHeaders} instance containing the information about the sections present in the PE file.
          
          @rtype: str
          @return: A string with the overlay data from the PE file.
          
          @raise InstanceErrorException: If the C{readDataInstance} or the C{sectionHdrsInstance} were not specified.