How to make conversion between RGB and HSV? [Python sourcecode]

I get following codes from a Japanese Ghost's Blog, so I neglect the original URL for my hate of them.
RGB => HSV
def RGB2HSV( r, g, b ): r, g, b = map( float, (r,g,b ) ) if r == g and g == b: ma = r mi = r h = 0 v = r elif r > g and r > b: ma = r mi = min( g , b ) h = 60 * ( g - b ) / ( ma - mi ) + 0 elif g > b and g >= r: ma = g mi = min( b , r ) h = 60 * ( b - r ) / ( ma - mi ) + 120 elif b >= r and b >= g: ma = b mi = min( r , g ) h = 60 * ( r - g ) / ( ma - mi ) + 240 else: print "Error."
if ma == 0: return 0, 0, 0 s = (ma - mi) / ma v = ma
return h, s, v

HSV => RGB
def HSV2RGB( h, s, v ): hi = int(h / 60) % 6 f = h / 60 - hi p = v * ( 1 - s ) q = v * ( 1 - f * s ) t = v * ( 1 - ( 1 - f ) * s )
if hi == 0: r = int(round( v )) g = int(round( t )) b = int(round( p )) elif hi == 1: r = int(round( q )) g = int(round( v )) b = int(round( p )) elif hi == 2: r = int(round( p )) g = int(round( v )) b = int(round( t )) elif hi == 3: r = int(round( p )) g = int(round( q )) b = int(round( v )) elif hi == 4: r = int(round( t )) g = int(round( p )) b = int(round( v )) elif hi == 5: r = int(round( v )) g = int(round( p )) b = int(round( q )) return r, g, b