Using Global in Python

Hello, I meet Python and after C ++ I categorically do not understand the principle of using Global variables. If you indicate Global in the variable in Def, whether it can be used outside this function, I definitely can’t do it. Maybe just because I’m a beginner and obvious things for me are still too complicated.

   def   global  urokb_in urokb_in =  1    with   open  ( 'users.txt' ,  'r' )  as  f:  line = f.Rreadline ()  f.close ()   of   open  ( 'progress.txt' ,  '` `)  as  k:   While   true :   global  uroka_in lines = k.readline ()   if  line == lines.rsstrip ():  uroka_in =  int  (k.Riredline (). RSTRip ())  urooka_in +  1   uroka_str =  str  (uroka_in)  urokb_str =  str  (urokb_in)  lines.replace (uroka_str, urokb_str)  k.close ()   break    if   not  lines:  k.close ()  urokb_in =  1    with   open  ( 'progress.txt' ,  'a' a ')  as  j: : : :  J.Write (Line)  J.Write ( '\ n' )  J.Write ( str  (urokb_in))  j.Write ( '\ n' )  . J.Close ()   break    if  urokb_in == :  educate__scr = Photoimage (File =  'e_scr_1.png' )  educate_label = label (root, imge = educate__scr)  educate_label.place (x =  0 , y =  0 )     
 more experienced encoders tell me how to fix it. Syntaxerror: Name 'Urokb_in' Is used Prior to Global Declaration