fun CharSequence.isDigitsOnly(): Boolean
Returns whether the given CharSequence contains only digits.
fun CharSequence.toSpannable(): Spannable
Returns a new Spannable from CharSequence,
or the source itself if it is already an instance of SpannableString.
fun CharSequence.toSpanned(): Spanned
Returns a new Spanned from CharSequence,
or the source itself if it is already an instance of SpannedString.
fun CharSequence.trimmedLength(): Int
Returns the length that the specified CharSequence would have if spaces and ASCII control
characters were trimmed from the start and end, as by String.trim.