code: def get_current_line(self):
          
          if not self.has_space():
              return None
  
          pos = self.pos - self.col
          string = self.string
          end = self.length
  
          output = []
          while pos < len(string) and string[pos] != '\n':
              output.append(string[pos])
              pos += 1
              if pos == end:
                  break
          else:
              output.append(string[pos])
  
          if not output:
              return None
  
          return SourceLine(''.join(output), self.row)
docs: Return a SourceLine of the current line.