(palette)
return p
Check a palette argument (to the :class:`Writer` class) for validity.
    Returns the palette as a list if okay; raises an exception otherwise.
Check a palette argument (to the :class:`Writer` class) for validity.
    Returns the palette as a list if okay; raises an exception otherwise.
Check a palette argument ( to the : class : Writer class ) for validity . Returns the palette as a list if okay ; raises an exception otherwise .
def check_palette(palette):
    """Check a palette argument (to the :class:`Writer` class) for validity.
    Returns the palette as a list if okay; raises an exception otherwise.
    """

    # None is the default and is allowed.
    if palette is None:
        return None

    p = list(palette)
    if not (0 < len(p) <= 256):
        raise ValueError("a palette must have between 1 and 256 entries")
    seen_triple = False
    for i,t in enumerate(p):
        if len(t) not in (3,4):
            raise ValueError(
              "palette entry %d: entries must be 3- or 4-tuples." % i)
        if len(t) == 3:
            seen_triple = True
        if seen_triple and len(t) == 4:
            raise ValueError(
              "palette entry %d: all 4-tuples must precede all 3-tuples" % i)
        for x in t:
            if int(x) != x or not(0 <= x <= 255):
                raise ValueError(
                  "palette entry %d: values must be integer: 0 <= x <= 255" % i)
    return p
def check_palette ( palette ) : # None is the default and is allowed. if palette is None : return None p = list ( palette ) if not ( 0 < len ( p ) <= 256 ) : raise ValueError ( "a palette must have between 1 and 256 entries" ) seen_triple = False for i , t in enumerate ( p ) : if len ( t ) not in ( 3 , 4 ) : raise ValueError ( "palette entry %d: entries must be 3- or 4-tuples." % i ) if len ( t ) == 3 : seen_triple = True if seen_triple and len ( t ) == 4 : raise ValueError ( "palette entry %d: all 4-tuples must precede all 3-tuples" % i ) for x in t : if int ( x ) != x or not ( 0 <= x <= 255 ) : raise ValueError ( "palette entry %d: values must be integer: 0 <= x <= 255" % i ) return p