How to avoid exec(), globals(), locals(), eval()

[snippsat]

I'm doing my best to have a good practice

Then can play a song at right moment The PEP 8 Song🎵
In this post an your other post your code look messy when look at it for having good practice in Python.
So i rewrite it would look like this and code works.

import numpy as np

# Make random numpy array
mat = np.random.random((10,1))
mat2 = np.random.random((10,1))
mat3 = np.random.random((10,1))

my_dict = {"new_dict": {'mat1': mat, 'mat2': mat2}}
# dict to add
basic_dict = {'mat': mat}
new_key = 'new_key'
if not new_key in my_dict:
    print(f"{new_key} is not in my_dictList -> added")
    my_dict.update({new_key: {}, })
    my_dict.update(basic_dict)
else:
    print(f"{new_key} is in my_dict")

# Test my_dict
get_mat2 = my_dict['new_dict']['mat2']
print(get_mat2)
print('-' * 25)
print(my_dict)

Output:
new_key is not in my_dictList -> added
[[0.85424998]
 [0.75364254]
 [0.76795389]
 [0.43357187]
 [0.37357796]
 [0.71517631]
 [0.69691738]
 [0.43317861]
 [0.95802329]
 [0.26230435]]
-------------------------
{'new_dict': {'mat1': array([[0.91394191],
       [0.8892786 ],
       [0.48059377],
       [0.92667453],
       [0.1901234 ],
       [0.3502345 ],
       [0.08907687],
       [0.38634954],
       [0.98999417],
       [0.02432816]]), 'mat2': array([[0.85424998],
       [0.75364254],
       [0.76795389],
       [0.43357187],
       [0.37357796],
       [0.71517631],
       [0.69691738],
       [0.43317861],
       [0.95802329],
       [0.26230435]])}, 'new_key': {}, 'mat': array([[0.91394191],
       [0.8892786 ],
       [0.48059377],
       [0.92667453],
       [0.1901234 ],
       [0.3502345 ],
       [0.08907687],
       [0.38634954],
       [0.98999417],
       [0.02432816]])}