code: def chmod(self, target_file, acl='public-read'):
          
          self.k.key = target_file  # setting the path (key) of file in the container
          self.k.set_acl(acl)  # setting the file permissions
          self.k.close()
docs: sets permissions for a file on S3
  
          Parameters
          ----------
  
          target_file : string
              Path to file on S3
  
          acl : string, optional
              File permissions on S3. Default is public-read
  
              options:
                  - private: Owner gets FULL_CONTROL. No one else has any access rights.
                  - public-read: Owners gets FULL_CONTROL and the anonymous principal is granted READ access.
                  - public-read-write: Owner gets FULL_CONTROL and the anonymous principal is granted READ and WRITE access.
                  - authenticated-read: Owner gets FULL_CONTROL and any principal authenticated as a registered Amazon S3 user is granted READ access
  
  
          Examples
          --------
              >>> s3utils.chmod("path/to/file","private")