How to iterate pixels with python API?

[Scallact]

Just a little Post-Scriptum about the Babl pixel format in the .set_rectangle method.
Here are the formats that I could gather from the internet, notably from here:

• u... are for integer
  
• RGB are for linear values
  
• R'G'B' are for non-linear values (ie, with a perceptual color profile)
  
• A is always linear 
  

The formats:

• RGB u8
  
• RGBA u8
  
• RGBA float
  
• R'G'B' u8
  
• R'G'B'A u8
  
• R'G'B'A float
  

The formats I presume should logically exist (correct me if wrong):

• RGB u16
  
• RGBA u16
  
• R'G'B' u16
  
• R'G'B'A u16
  
• RGB u32
  
• RGBA u32
  
• R'G'B' u32
  
• R'G'B'A u32
  
• RGB float
  
• R'G'B' float