code: def fix_string_case(text):
      
      fixed = []
      for i in text:
          if is_case_sensitive(i):
              fixed.append(i)
          else:
              fixed.append(i.lower())
      return ''.join(fixed)
docs: Converts case-insensitive characters to lower case
  
      Case-sensitive characters as defined in config.AVRO_CASESENSITIVES
      retain their case, but others are converted to their lowercase
      equivalents. The result is a string with phonetic-compatible case
      which will the parser will understand without confusion.