str = 'Python'
print(str.isidentifier())

str = 'Py thon'
print(str.isidentifier())

str = '22Python'
print(str.isidentifier())

str = ''
print(str.isidentifier())

str = 'root33'
if str.isidentifier() == True:
  print(str, 'is a valid identifier.')
else:
  print(str, 'is not a valid identifier.')
  
str = '33root'
if str.isidentifier() == True:
  print(str, 'is a valid identifier.')
else:
  print(str, 'is not a valid identifier.')
  
str = 'root 33'
if str.isidentifier() == True:
  print(str, 'is a valid identifier.')
else:
  print(str, 'is not a valid identifier.')