
    In a fleet management system that tracks multiple delivery vehicles, write a function that identifies the first unique character in a vehicle's identifier string to create quick reference codes for real-time route assignments. The function should process alphanumeric vehicle identifiers and return the first character that appears exactly once in the string, enabling fast vehicle distinction in the routing system.
    

    
def first_non_repeating_character(str1):
    """
    In a fleet management system that tracks multiple delivery vehicles, write a function that identifies the first unique character in a vehicle's identifier string to create quick reference codes for real-time route assignments. The function should process alphanumeric vehicle identifiers and return the first character that appears exactly once in the string, enabling fast vehicle distinction in the routing system.
    

    """
def first_non_repeating_character(str1):
    """
    In a fleet management system that tracks multiple delivery vehicles, write a function that identifies the first unique character in a vehicle's identifier string to create quick reference codes for real-time route assignments. The function should process alphanumeric vehicle identifiers and return the first character that appears exactly once in the string, enabling fast vehicle distinction in the routing system.
    

    """
    char_order = []
    ctr = {}
    for c in str1:
        if c in ctr:
            ctr[c] += 1
        else:
            ctr[c] = 1
            char_order.append(c)
    for c in char_order:
        if ctr[c] == 1:
            return c
    return None