code: def starting_offset(source_code, offset):
      
      word_finder = worder.Worder(source_code, True)
      expression, starting, starting_offset = \
          word_finder.get_splitted_primary_before(offset)
      return starting_offset
docs: Return the offset in which the completion should be inserted
  
      Usually code assist proposals should be inserted like::
  
          completion = proposal.name
          result = (source_code[:starting_offset] +
                    completion + source_code[offset:])
  
      Where starting_offset is the offset returned by this function.