Work function endlessly loops and when I set WORK_DONE as -1, no output is shown - gnuradio

Question

I'm currently trying to implement my own source block on GNURADIO. What this source block does is takes the values of 4 arguments (titled Value1,Value2,Value3 and Value4) and converts them to binary values with varying lengths. For example, Value1 is converted into a binary value with a length of 11 bits, whilst Value2 is converted into a binary value with a length of 16 bits etc. The conversion of these values work.
The issue I'm having is that I am unable to output these converted values onto a vector sink. when the work function returns (len(output[0]),when I execute the code using QA code. I end up with an endless loop, which when interrupted, outputs an extremely large vector with values of "0L".
Now from reading similar questions, I understand that as my block is set as a source, it will send out data as long as the vector sink has enough room in its input buffer. Therefore I set the return value to be -1 to force the flow graph to stop. This gives me an empty value "()" in the Vector sink.
The code is shown below:
import numpy
import time
import sys
import random
import os
from gnuget import *
from gnuradio import gr
from gnuradio import blocks
from gnuradio.blocks.blocks_swig1 import vector_source_b
class ConvertVariables(gr.sync_block):
"""
docstring for block ConvertVariables
"""
def __init__(self,Value1,Value2,Value3,Value4):
self.value1 = Value1
self.value2 = Value2
self.value3 = Value3
self.value4 = Value4
gr.sync_block.__init__(self,
name="ConvertVariables",
in_sig=None,
out_sig=[(numpy.byte)])
def work(self, input_items, output_items):
out = output_items[0]
self.value1_R = getvalue1(self.value1)
self.value2_R = getvalue2(self.value2)
self.value3_R = getvalue3(self.value3)
self.value4_R = getvalue4(self.value4)
self.value1_B = bytearray(self.value1_R,'utf-8')
self.value2_B = bytearray(self.value2_R,'utf-8')
self.value3_B = bytearray(self.value3_R,'utf-8')
self.value4_B = bytearray(self.value4_R,'utf-8')
print(type(self.value1_B))
print(type(self.value2_B))
print(type(self.value3_B))
print(type(self.value4_B))
print(len(output_items),"output_items")
self.out[:] = [self.value1_B,self.value2_B,self.value3_B,self.value4_B]
print(len(output_items[0]))
return (len(output_items[0]))
So ideally when the arguments(2034,5000,50,5) are sent. The expected result in the vector sink is
('11111110010','0001001110001000','110010','0101')
However what appears instead is either
(0L,0L,0L,0L)
(The length of the vector is not consistent, if I set the return value of work to len(output[0]), the terminal windows fills with 0L)
or
()
This only occurs if the return value of work is set to -1