Working with file policies can be sometimes a pain.
You must have the UUID of the policy, the size that is required in the long format e.g. 2 GB = 2147483648L
FilesPolicyService.edit("2d93497d-065a-4022ae25-a4b52598d11a", "My Policy", 2147483648L)
Using the cnxFilesPolicies.py script will allow you to add, edit or delete a file policy. The script will also list the policies on the system.
For instance to edit the community file policy and increase the size to 1 GB, select edit, select the policy number, you may rename a policy or press enter to leave the name the same, add the new size
When the policies are listed again the newly edited details are seen