Count Uppercase and Lowercase Letters in String

def uppercase_lowercase_count(text = "This Sentence Has Mixed CASE Letters!"):
    uppercase_count = 0
    lowercase_count = 0

    for char in text:
        if char.isalpha() and char.isupper():    # Check for upper characters and alphabetic characters only
            uppercase_count = uppercase_count + 1
        elif char.isalpha() and char.islower():  # Check for upper characters and alphabetic characters only
            lowercase_count = lowercase_count + 1

    return uppercase_count, lowercase_count

# Function call and result display
uppercase_count, lowercase_count = uppercase_lowercase_count()

print(f"The number of uppercase letter is: {uppercase_count}")
print(f"The number of lowercase letter is: {lowercase_count}")