I've been playing with a Raspberry Pi and working with simple circuits. I thought I had a decent understanding of pull up/pull down resistors, but then I purchased an Infrared Break-Beam sensor (https://www.adafruit.com/product/2167) and the instructions for it confused me in terms of pull up resistors. For a circuit with just a switch, I would use a pull up resistor as described here (Pull-up resistor - why input pin is pulled to ground when the switch is closed?) and am able to understand how it works with the explanation in this answer (https://electronics.stackexchange.com/a/339369/170831), using the resistive divider function (https://en.wikipedia.org/wiki/Voltage_divider#Resistive_divider). However, the instructions for the break-beam sensor describe it as an "open collector" and specify to incorporate a 10K pull-up resistor across the voltage supply wire and the digital signal wire (as shown below if I'm understanding correctly).
My trouble is, from what I've read about pull-up resistors, I would've thought the pull-up resistor would go only on the voltage supply wire, but perhaps I don't really understand how the IR receiver works. The diagram below is how I would've expected to incorporate a pull-up resistor, as well as a basic idea of how I thought the sensor works as a switch.
Is it possible to have pull-up resistors in parallel with other devices in a circuit? If so, how do you use the resistive divider function when the resistors are in parallel? I can build the circuit as specified in the instructions. I'd just like to have more of an understanding of how it works.