Just to clarify @dimay 's comment:
np.array receives two inputs, with the first being the data itself, and the second being the datatype. When you want two rows, you should be giving np.array a list of lists.
np.array tried to create a 1-d array with the elements [7, 7, 7], and the other [7, 7, 7] was thought to be a dtype, which leads to the error.
Just to clarify @dimay 's comment: np.array receives two inputs, with the first being the data itself, and the second being the datatype. When you want two rows, you should be giving np.array a list of lists. np.array tried to create a 1-d array with the elements [7, 7, 7], and the other [7, 7, 7] was thought to be a dtype, which leads to the error.