How do I convert a list of integers into bytes?

I have some numbers that represent bytes, and I want to make a bytes object from them, for example b"something"

Here's my attempt, for the record of "making some research". I tried to google it, but found only the other direction (bytes to list of numbers). My goal is b'\x04\x05\x06' from 4, 5, 6.

The intelhex lib is only because that's where I need the bytes object.

In [1]: from intelhex import IntelHex
In [2]: ih = IntelHex()
In [3]: addr=10
In [4]: a=5
In [5]: b=4
In [6]: c=255

In [7]: ih.puts(addr, bytes(a, b, c))
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-def738bb7624> in <module>()
----> 1 ih.puts(addr, bytes(a, b, c))

TypeError: bytes() argument 2 must be str, not int

In [8]: ih.puts(addr, b'{}{}{}'.format(a, b, c))
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-8-eabba8aef324> in <module>()
----> 1 ih.puts(addr, b'{}{}{}'.format(a, b, c))

AttributeError: 'bytes' object has no attribute 'format'

I'm probably doing some stupid mistake here, the bytes() function should do it.