#NEWLINE# def _errmsg( argname , ltd , errmsgExtra = '' ) : #NEWLINE# #INDENT# 'Construct an error message.\n\n    argname, string, the argument name.\n    ltd, string, description of the legal types.\n    errmsgExtra, string, text to append to error mssage.\n    Returns: string, the error message.\n    ' #NEWLINE# if errmsgExtra : #NEWLINE# #INDENT# errmsgExtra = ( '\n' + errmsgExtra ) #NEWLINE# #UNINDENT# return ( "arg '%s' must be %s%s" % ( argname , ltd , errmsgExtra ) )