Find the number of leaf nodes in a full k-ary tree of height m.
Note: You have to return the answer module 10^{9}+7.

Example 1:
Input:
k = 2, m = 2
Output:
4
Explanation:
A full Binary tree of height 2 has 4 leaf nodes.
Example 2:
Input:
k = 2, m = 1
Output:
2
Explanation:
A full Binary tree of height 1 has 2 leaf nodes.

Your Task:
You don't need to read input or print anything. Your task is to complete the function karyTree() which takes 2 Integers k, and m as input and returns the number of leaf nodes in a full k-ary Tree.

Expected Time Complexity: O(log(m))
Expected Auxiliary Space: O(1)

Constraints:
1 <= k,m <= 10^{8}

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