'Push a stack frame into the call stack. This method is called when calling a function in CFG recovery.
:param int callsite_addr: Address of the call site
:param int addr: Address of the call target
:param int or None retn_target: Address of the return target
:param int stack_pointer: Value of the stack pointer
:return: None'

def call(self, callsite_addr, addr, retn_target=None, stack_pointer=None):

    frame = CallStack(call_site_addr=callsite_addr, func_addr=addr, ret_addr=retn_target, stack_ptr=stack_pointer)
    return self.push(frame)
