Bad taste of code: control structure nesting too deep

Before reconstructionCode

     Def Newprj (self, DB, userid, prjname, password, privacy, Intro = '' , Status = '  Active  ' ):
S = '' 
Flag = false
Prjid = 0

 Try :
T = dB. Transaction ()
 If Privacy ='  Public  '   And Len (password) <1:
 Return   '  {"Result": "error", "message": "public access without a password. Anyone can join your project "}  ' 

Folderid, deep = tn. newfolder (dB, prjname, userid, 0, 0)
 If Folderid! = 0:
Prjid = dB. insert ( '  Project  ' , Folderid = folderid, userid = userid, projectname = prjname,
Password = password, privacy = privacy, Intro = intro, status = status,
Createtime = STR (datetime. datetime. Today (), revision = util. new_revision (dB, userid ))
DB. Update ( "  Category  " , Where = "  Catid = $ folderid  " , Projectid = prjid, deep =-1, vars = locals ())

 Import JSON
 From RoleImport Rolemgr
Rolemgr = rolemgr ()
S = rolemgr. newrole (dB, "  Project user  " , Prjid)
Dict = JSON. jsondecoder (). Decode (s)
 If Dict [ '  Result  ' ] = '  OK  ' :
Roleid = int (dict [ '  Roleid  ' ])
 If Rolemgr. bindpermission (dB, roleid, folderid, READ = 1, write = 0) = true:
Flag = true
S = '  {"Result": "OK", "prjid": "% d "}  ' % (INT (prjid ))
 Else :
S = ' {"Result": "error", "message": "failed to preset project role Permissions "}  ' 
 Else :
S = '  {"Result": "error", "message": "preset project role failed "}  ' 
 Else :
S = '  {"Result": "error", "message": "a folder with the same name exists "}  ' 

 If Flag = true:
T. Commit ()
 Else :
T. rollback ()

 Return S

 Except :
T. rollback ()

Code after reconstruction

 Def Newprj (dB, userid, projectname, password, privacy, intro, status = '  Active  ' ):
 Try :
T = dB. Transaction ()
Projectname = projectname. lstrip (). rstrip ()
 If   Not _ Checkname (projectname ):
T. rollback ()
 Return (False, "  Invalid project name  " )
Folderid, deep = tn. newfolder (dB, projectname, userid, 0, 0)
 If Folderid = 0:
T. rollback ()
 Return (False, " An error occurred while creating the project root directory.  " )
Projectid = _ insert (dB, projectname, folderid, userid, password, privacy, intro, status)
 If Projectid = 0:
T. rollback ()
 Return (False, "  An error occurred while creating the project.  " )
 If Folder. setrootfolder (dB, folderid, projectid) = false:
T. rollback ()
 Return (False,"  Failed to Set Directory  " )
 If _ Presetrole (dB, userid, folderid, projectid) = false:
T. rollback ()
 Return (False, "  An error occurred while creating the default role.  " )
 If _ Presetfolder (dB, userid, folderid) = false:
T. rollback ()
 Return (False, " An error occurred while creating the project directory.  " )

T. Commit ()
 Return (True, projectid)
 Except :
T. rollback ()
 Raise