new_contents: import numpy as np
  
  A = np.array([1, 2, 3, 4])
  print(A)
  
  # 1 array -> vector
  print(np.ndim(A))
  print(A.shape)
  print(A.shape[0])
  
  # 2 array -> matrix
  B = np.array([[1, 2], [3, 4], [5, 6]])
  print(B)
  print(np.ndim(B))
  print(B.shape)
  
  # calculate multiply
  C = np.array([[1, 2], [3, 4]])
  print(C.shape)
  D = np.array([[5, 6], [7, 8]])
  print(D.shape)
  print(np.dot(C, D))
  
  E = np.array([[1, 2, 3], [4, 5, 6]])
  print(E.shape)
  F = np.array([[1, 2], [3, 4], [5, 6]])
  print(F.shape)
  print(np.dot(E, F))
  
  G = np.array([[1, 2], [3, 4], [5, 6]])
  print(G.shape)
  H = np.array([7, 8])
  print(H.shape)
  print(np.dot(G, H))
  
subject: Add calculate_numpy