Checking for monotonic array in Python

def isMonotonic(A):
   return (all(A[i] <= A[i + 1] for i in range(len(A) - 1)) or
      all(A[i] >= A[i + 1] for i in range(len(A) - 1)))
# main
A = [5,6,7,8,9,10,11,12]
print(isMonotonic(A))

def isMonotonic(A):
   return (all(A[i] <= A[i + 1] for i in range(len(A) - 1)) or
      all(A[i] >= A[i + 1] for i in range(len(A) - 1)))
# main
A = [0, 8, 12, 15, 16, 1, 2, 4]
print(isMonotonic(A))