<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Implement a function that takes a character and returns true if the character is an uppercase letter.
<|im_end|>
<|im_start|>assistant
function isUpperCase(ch) {
  if (ch.charCodeAt(0) >= 65 && ch.charCodeAt(0) <= 90) {
    return true;
  }
  return false;
}<|im_end|>
