code: def wash_line(line):
      
      line = re_space_comma.sub(',', line)
      line = re_space_semicolon.sub(';', line)
      line = re_space_period.sub('.', line)
      line = re_colon_space_colon.sub(':', line)
      line = re_comma_space_colon.sub(':', line)
      line = re_space_closing_square_bracket.sub(']', line)
      line = re_opening_square_bracket_space.sub('[', line)
      line = re_hyphens.sub('-', line)
      line = re_multiple_space.sub(' ', line)
      return line
docs: Wash a text line of certain punctuation errors, replacing them with
         more correct alternatives.  E.g.: the string 'Yes , I like python.'
         will be transformed into 'Yes, I like python.'
         @param line: (string) the line to be washed.
         @return: (string) the washed line.