'Create a new MemoryRegion with the region key specified, and store it to self._regions.
:param key: a string which is the region key
:param state: the SimState instance
:param bool is_stack: Whether this memory region is on stack. True/False
:param related_function_addr: Which function first creates this memory region. Just for reference.
:param endness: The endianness.
:param backer_dict: The memory backer object.
:return: None'

def create_region(self, key, state, is_stack, related_function_addr, endness, backer_dict=None):

    self._regions[key] = MemoryRegion(key, state=state, is_stack=is_stack, related_function_addr=related_function_addr, endness=endness, backer_dict=backer_dict)
