def get_unused_var_name(prefix, var_table):
    """ Get a new var name with a given prefix and
        make sure it is unused in the given variable table.
    """
    cur = 0
    while True:
        var = prefix + str(cur)
        if var not in var_table:
            return var
        cur += 1
 Get a new var name with a given prefix and
        make sure it is unused in the given variable table.
    
numba/core/ir_utils.py