code: def validateDayOfWeek(value, blank=False, strip=None, allowlistRegexes=None, blocklistRegexes=None, dayNames=ENGLISH_DAYS_OF_WEEK, excMsg=None):
      
  
      # TODO - reuse validateChoice for this function
  
      # returns full day of the week str, e.g. 'Sunday'
  
      # Reuses validateMonth.
      try:
          return validateMonth(value, blank=blank, strip=strip, allowlistRegexes=allowlistRegexes, blocklistRegexes=blocklistRegexes, monthNames=ENGLISH_DAYS_OF_WEEK)
      except:
          # Replace the exception message.
          _raiseValidationException(_('%r is not a day of the week') % (_errstr(value)), excMsg)
docs: Raises ValidationException if value is not a day of the week, such as 'Mon' or 'Friday'.
      Returns the titlecased day of the week.
  
      * value (str): The value being validated as a day of the week.
      * blank (bool):  If True, a blank string will be accepted. Defaults to False.
      * strip (bool, str, None): If None, whitespace is stripped from value. If a str, the characters in it are stripped from value. If False, nothing is stripped.
      * allowlistRegexes (Sequence, None): A sequence of regex str that will explicitly pass validation, even if they aren't numbers.
      * blocklistRegexes (Sequence, None): A sequence of regex str or (regex_str, response_str) tuples that, if matched, will explicitly fail validation.
      * dayNames (Mapping): A mapping of uppercase day abbreviations to day names, i.e. {'SUN': 'Sunday', ...} The default provides English day names.
      * excMsg (str): A custom message to use in the raised ValidationException.
  
      >>> import pysimplevalidate as pysv
      >>> pysv.validateDayOfWeek('mon')
      'Monday'
      >>> pysv.validateDayOfWeek('THURSday')
      'Thursday'