Transpose, symmetric and skew parts

You will write the transpose of a matrix, a test for a symmetric matrix, and the skew-symmetric part of a square matrix. A matrix is a list of rows. The checker tests many matrices.

The idea. The entry in row $i$, column $j$ of $A^T$ is A[j][i]. A square matrix is symmetric when it equals its transpose. The skew-symmetric part has the entry $\tfrac{1}{2}(a_{ij} - a_{ji})$ in row $i$, column $j$.

Your tasks.

1. Finish transpose(A). Return the transpose as a list of rows.
2. Finish is_symmetric(A). Return True or False.
3. Finish skew_part(A). Return the skew-symmetric part of a square matrix.