function isUpperCase(subject) {
    var subjectString = coerceToString(subject);
    return isAlpha(subjectString) && subjectString.toUpperCase() === subjectString;
  }
Checks whether `subject` contains only upper case characters.

@function isUpperCase
@static
@since 1.0.0
@memberOf Query
@param {string} [subject=''] The string to verify.
@return {boolean} Returns `true` if `subject` is upper case or `false` otherwise.
@example
v.isUpperCase('ACDC');
// => true

v.isUpperCase('Morning');
// => false