The 25 means that that process is using an average of 25% usage among all of your logical processors (aka cores). So if you had 4 logical processors in your CPU, that might mean that the 25% is running one logical processor at 100% and the others at 0 or that 25% is divided among several logical processors.
I think Python apps can't use multiple logical processors, so you might want to look into multi-core processing in Python if you want Python to use more of your CPU.
You can also limit the amount of logical processors Python uses by right-clicking on the process and selecting "Set Affinity". Selecting " Priority" will also let you choose how much of a priority that process is compared to other processes.
You can also monitor each logical processor's usage in the next tab after that, just make sure the graph is set to show logical processors, not average CPU usage.