parameters: (self, file=None)
docstring: print_usage(file : file = stdout)
  
          Print the usage message for the current program (self.usage) to
          'file' (default stdout).  Any occurrence of the string "%prog" in
          self.usage is replaced with the name of the current program
          (basename of sys.argv[0]).  Does nothing if self.usage is empty
          or not defined.
docstring_summary: print_usage(file : file = stdout)
docstring_tokens: print_usage ( file : file = stdout )
function: def print_usage(self, file=None):
          """print_usage(file : file = stdout)
  
          Print the usage message for the current program (self.usage) to
          'file' (default stdout).  Any occurrence of the string "%prog" in
          self.usage is replaced with the name of the current program
          (basename of sys.argv[0]).  Does nothing if self.usage is empty
          or not defined.
          """
          if self.usage:
              print >>file, self.get_usage()
function_tokens: def print_usage ( self , file = None ) : if self . usage : print >> file , self . get_usage ( )