<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def clean_zeros(a, b, M):
 """ Remove all components with zeros weights in a and b """

    M2 = M[a > 0, :][:, b > 0].copy()  # copy force c style matrix (froemd)
    a2 = a[a > 0]
    b2 = b[b > 0]
    return a2, b2, M2