
    In a banking system's credit risk assessment module, develop a function that identifies the first unique character in a loan application's transaction ID string, which will be used as a quick reference index in the risk assessment database. The function should process alphanumeric transaction IDs of varying lengths and return the first character that appears exactly once in the ID string.
    

    
def first_non_repeating_character(str1):
    """
    In a banking system's credit risk assessment module, develop a function that identifies the first unique character in a loan application's transaction ID string, which will be used as a quick reference index in the risk assessment database. The function should process alphanumeric transaction IDs of varying lengths and return the first character that appears exactly once in the ID string.
    

    """
def first_non_repeating_character(str1):
    """
    In a banking system's credit risk assessment module, develop a function that identifies the first unique character in a loan application's transaction ID string, which will be used as a quick reference index in the risk assessment database. The function should process alphanumeric transaction IDs of varying lengths and return the first character that appears exactly once in the ID string.
    

    """
    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