def _classify_point(re, im):
 if ((not re) and (not im)):
  return OO
 if (not re):
  if (im > 0):
   return A2
  else:
   return A4
 elif (not im):
  if (re > 0):
   return A1
  else:
   return A3

def _classify_point ( re , im ) : if ( ( not re ) and ( not im ) ) : return OO if ( not re ) : if ( im > 0 ) : return A2 else : return A4 elif ( not im ) : if ( re > 0 ) : return A1 else : return A3
return the half-axis on which point is located .