How to use the munch.IT214Exception function in munch

vpos = 0
		vmask = (1<= self.brem:
			if self.dpos >= len(self.data):
				raise IT214Exception("unbalanced block end")
			
			v |= (ord(self.data[self.dpos])>>self.bpos)< 0:
			if self.dpos >= len(self.data):
				raise IT214Exception("unbalanced block end")
			
			v |= (ord(self.data[self.dpos])>>self.bpos)<

def unpack(self):
		#while self.grab_length > 0:
		# I think THIS is what itsex.c meant. --GM
		self.length = min(self.grab_length,self.maxgrablen)
		self.grab_length -= self.length
		print "subchunk length: %i" % self.length
		self.unpacked_root = 0
		while self.length > 0 and not self.end_of_block():
			if self.width == 0 or self.width > self.widthtop:
				raise IT214Exception("invalid bit width")
			
			v = self.read(self.width)
			topbit = (1<<(self.width-1))
			#print self.width,v
			if self.width <= 6: # MODE A
				if v == topbit:
					self.change_width(self.read(self.fetch_a))
					#print self.width
				else:
					self.write(self.width, v, topbit)
			elif self.width < self.widthtop: # MODE B
				if v >= topbit+self.lower_b and v <= topbit+self.upper_b:
					qv = v - (topbit+self.lower_b)
					#print "MODE B CHANGE",self.width,v,qv
					self.change_width(qv)
					#print self.width

def read(self, width):
		v = 0
		vpos = 0
		vmask = (1<= self.brem:
			if self.dpos >= len(self.data):
				raise IT214Exception("unbalanced block end")
			
			v |= (ord(self.data[self.dpos])>>self.bpos)< 0:
			if self.dpos >= len(self.data):
				raise IT214Exception("unbalanced block end")
			
			v |= (ord(self.data[self.dpos])>>self.bpos)<