code: def remove_imath_operators(lines):
          
          for idx, line in enumerate(lines):
              for operator in ('+=', '-=', '**=', '*=', '//=', '/=', '%='):
                  sublines = line.split(operator)
                  if len(sublines) > 1:
                      indent = line.count(' ') - line.lstrip().count(' ')
                      sublines = [sl.strip() for sl in sublines]
                      line = ('%s%s = %s %s (%s)'
                              % (indent*' ', sublines[0], sublines[0],
                                 operator[:-1], sublines[1]))
                      lines[idx] = line
docs: Remove mathematical expressions that require Pythons global
          interpreter locking mechanism.
  
          This is not a exhaustive test, but shows how the method works:
  
          >>> lines = ['    x += 1*1']
          >>> from hydpy.cythons.modelutils import FuncConverter
          >>> FuncConverter.remove_imath_operators(lines)
          >>> lines
          ['    x = x + (1*1)']