<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def transpose_mat44(src_mat, transpose_mat=None):
 """Create a transpose of a matrix."""


    if not transpose_mat:
        transpose_mat = Matrix44()

    for i in range(4):
        for j in range(4):
            transpose_mat.data[i][j] = src_mat.data[j][i]

    return transpose_mat