code: def build_tokens_line(self):
          
          self.mapping = []
          logical = []
          length = 0
          previous = None
          for token in self.tokens:
              token_type, text = token[0:2]
              if token_type in (tokenize.COMMENT, tokenize.NL,
                                tokenize.INDENT, tokenize.DEDENT,
                                tokenize.NEWLINE):
                  continue
              if token_type == tokenize.STRING:
                  text = mute_string(text)
              if previous:
                  end_line, end = previous[3]
                  start_line, start = token[2]
                  if end_line != start_line: # different row
                      if self.lines[end_line - 1][end - 1] not in '{[(':
                          logical.append(' ')
                          length += 1
                  elif end != start: # different column
                      fill = self.lines[end_line - 1][end:start]
                      logical.append(fill)
                      length += len(fill)
              self.mapping.append((length, token))
              logical.append(text)
              length += len(text)
              previous = token
          self.logical_line = ''.join(logical)
          assert self.logical_line.lstrip() == self.logical_line
          assert self.logical_line.rstrip() == self.logical_line
docs: Build a logical line from tokens.