old_contents: # numbers
  x = 1
  assert x.__class__ == int
  assert isinstance(x,int)
  assert str(x)=="1"
  
  assert 2+2==4
  assert (50-5*6)/4 == 5.0
  assert 8/5 == 1.6
  assert 7//3 == 2
  assert 7//-3 == -3
  width=20
  height=5*9
  assert width*height == 900
  x=y=z=0
  assert x == 0
  assert y == 0
  assert z == 0
  
  assert 3 * 3.75 / 1.5 == 7.5
  assert 7.0 / 2 == 3.5
  
  y=3.14
  assert y.__class__ == float
  assert isinstance(3.14,float)
  assert str(y)=="3.14"
  
  x = -3
  assert x.__abs__() == 3
  assert -x.__abs__() == -3
  
  assert x.__ceil__() == x
  assert x.__ceil__() == -3
  
  assert x.__divmod__(2) == (-2, 1)
  
  # complex numbers
  x = 8j
  y = 8.3j
  z = 3.2e6j
  a = 4+2j
  b = 2-3j
  c = 3.0-3j
  
  assert a*b == 14 - 8j
  assert x*x == -64
  assert x-7j == 1j
  assert -7j+x == 1j
  assert x-2.0j == 6j
  assert 1/a == 0.2 - 0.1j
  assert 2.0/a == 0.4 - 0.2j
  assert 1+a == 5+2j
  assert 2-a == -2-2j
  assert 3*a == 12+6j
  assert 1.0+a == 5+2j
  assert 2.0-a == -2-2j
  assert 3.0*a == 12+6j
  
  print('passed all tests...')
  
new_contents: # numbers
  x = 1
  assert x.__class__ == int
  assert isinstance(x,int)
  assert str(x)=="1"
  
  assert 2+2==4
  assert (50-5*6)/4 == 5.0
  assert 8/5 == 1.6
  assert 7//3 == 2
  assert 7//-3 == -3
  width=20
  height=5*9
  assert width*height == 900
  x=y=z=0
  assert x == 0
  assert y == 0
  assert z == 0
  
  assert 3 * 3.75 / 1.5 == 7.5
  assert 7.0 / 2 == 3.5
  
  y=3.14
  assert y.__class__ == float
  assert isinstance(3.14,float)
  assert str(y)=="3.14"
  
  x = -3
  assert x.__abs__() == 3
  assert -x.__abs__() == -3
  
  assert x.__ceil__() == x
  assert x.__ceil__() == -3
  
  assert x.__divmod__(2) == (-2, 1)
  
  # complex numbers
  x = 8j
  y = 8.3j
  z = 3.2e6j
  a = 4+2j
  b = 2-3j
  c = 3.0-3j
  
  assert a*b == 14 - 8j
  assert x*x == -64
  assert x-7j == 1j
  assert -7j+x == 1j
  assert x-2.0j == 6j
  assert 1/a == 0.2 - 0.1j
  assert 2.0/a == 0.4 - 0.2j
  assert 1+a == 5+2j
  assert 2-a == -2-2j
  assert 3*a == 12+6j
  assert 1.0+a == 5+2j
  assert 2.0-a == -2-2j
  assert 3.0*a == 12+6j
  
  assert hash(1.0) == 1
  
  print('passed all tests...')
  
subject: Add a test in test_numbers.py