<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def from_pickle(cls, filename):
 """Loads and Returns a Mesh from a pickle file, given a filename."""

        with open(filename, 'rb') as f:
            mesh = pickle.load(f).copy()
        return mesh