How to check whether a variable exists or not?

To check the existence of a local variable:

myVar = 10

if 'myVar' in locals():
	print(myVar)
else:
	print('None')

if 'myNum' in locals():
	print(myNum)
else:
	print('None')

To check the existence of a global variable:

myVar = 10

if 'myVar' in globals(): print(myVar)
else: print('None')

if 'myNum' in globals(): print(myNum)
else: print('None')

To check if an object has an attribute:

if hasattr(obj, 'attr\_name'): print(obj)
else: print('None')

#References
https://stackoverflow.com/questions/843277/how-do-i-check-if-a-variable-exists