code: def is_letter(uni_char):
      
      category = Category.get(uni_char)
      return (category == Category.UPPERCASE_LETTER or
              category == Category.LOWERCASE_LETTER or
              category == Category.TITLECASE_LETTER or
              category == Category.MODIFIER_LETTER or
              category == Category.OTHER_LETTER)
docs: Determine whether the given Unicode character is a Unicode letter