remap with input error checking

some thoughts on the remap function, this includes some invalid input checking.

# remap.py python 3.2 blender 2.57 r37243
# GPL2 license
# Author Dealga McArdle

import bpy  
from mathutils import Vector  
  
def remap(current, lower_old, upper_old, lower_new, upper_new):
    '''  
    Remaps one range of values to another range of values, types must be float
        
    arguments   :   Description
    ----------------------------------------------------------
    current     :   Value to fit within the destination range
    lower_old   :   Lowest value of the original range
    upper_old   :   Highest value of the original range
    lower_new   :   Lowest value of the destination range
    upper_new   :   Highest value of the destination range
        
    '''

    # type checking, if any of the arguments are not float then return None.
    lcheck = current, lower_old, upper_old, lower_new, upper_new
    lstr = "current", "lower_old", "upper_old", "lower_new", "upper_new"
    
    for i in range(len(lcheck)):
        if lcheck[i].__class__ is not float: 
            print(lstr[i], "is not a float")
            return None
    
    # before calculations we can deal with some possible errors
    if current <= lower_old: return lower_new
    if current >= upper_old: return upper_new
      
    # reusing a nicely coded Vector math utility :)      
    old_min = Vector((0.0, 0.0, lower_old))  
    old_max = Vector((0.0, 0.0, upper_old))  
    new_min = Vector((0.0, 0.0, lower_new))  
    new_max = Vector((0.0, 0.0, upper_new))  
      
    # calculate spread, fast and saves room!   
    spread_old = (old_max-old_min).length  
    spread_new = (new_max-new_min).length  
    factor_remap = spread_new / spread_old  
      
    current_vector = Vector((0.0, 0.0, current))  
    remap_temp = (current_vector-old_min).length  
    remapped = (remap_temp * factor_remap) + new_min[2]  
        
    # clamp output when rounding creates values beyond new range
    if remapped < lower_new: return lower_new  
    if remapped > upper_new: return upper_new  
  
    # value seems alright!    
    return remapped