import warnings
import sys

class Printer(object):
    """An abstract class that prints out warning and
    information messages."""
    
    def info(self, msg):
        """Print out an information message.
        
        This will be used for fairly verbose information
        that's not normally wanted."""       
        
        raise NotImplementedError
    
    def warn(self, msg, t):
        """Print out a warning message of type t."""
        
        raise NotImplementedError
        
class SilentPrinter(Printer):
    """A printer that doesn't really print anything."""
    
    def info(self, msg):
        pass
    
    def warn(self, msg, t):
        pass
    
class NormalPrinter(SilentPrinter):
    """A printer that only shows warnings."""
    
    def warn(self, msg, t):
        warnings.warn(msg, t, 2)

class VerbosePrinter(NormalPrinter):
    """A printer that shows everything."""
    
    def info(self, msg):
        print msg
        sys.stdout.flush()