<|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
Create a function to check if a string contains only unique characters.
string = "Programming"<|im_end|>
<|im_start|>assistant
def unique_chars(string):
    # List to keep track of characters 
    characters = []
    
    for c in string:
        if c not in characters:
            characters.append(c)
        else:  
            return False
    
    return True<|im_end|>
