def toString(self):
        """
        Returns a string representation of Layer instance.
        """
        string = "Layer '%s': (Kind: %s, Size: %d, Active: %d, Frozen: %d)\n" % (
            self.name, self.kind, self.size, self.active, self.frozen) 
        if (self.type == 'Output'):
            string += toStringArray('Target    ', self.target, self.displayWidth)
        string += toStringArray('Activation', self.activation, self.displayWidth) 
        if (self.type != 'Input' and self._verbosity > 1):
            string += toStringArray('Error     ', self.error, self.displayWidth)
        if (self._verbosity > 4 and self.type != 'Input'):
            string +=  toStringArray('weight    ', self.weight, self.displayWidth)
            string +=  toStringArray('dweight   ', self.dweight, self.displayWidth)
            string +=  toStringArray('delta     ', self.delta, self.displayWidth)
            string +=  toStringArray('netinput  ', self.netinput, self.displayWidth)
            string +=  toStringArray('wed       ', self.wed, self.displayWidth)
        return string
Returns a string representation of Layer instance.