def verlet(atom_coord,forces,dtstep,old_atom_coord,mass):
    """
    This function gets as input parameters:
    - `atom_coord`, a vector containing the x and y position and the charge of the i atoms
    - `old_atom_coord`, a vector containing the x and y positions from the previous MD step
    - `forces`, a vector containing the x and y components of the force on the atoms
    - `dtstep`, the integration time step
    The function returns a list containing the new positions.

    Implement in the following loop between the arrows the Verlet MD algorithm.
    A few hints:
    - Powers in python are given by **, e.g.: x to the square is `x**2`
    - Squared root x: `sqrt(x)`
    - Indents are important in python
    """

    new_positions=[]
    for coord,old_coord,force  in zip(atom_coord, old_atom_coord, forces):
        r0x=coord[0]			# Coordinates
        r0y=coord[1]
        old_r0x=old_coord[0]		# Old coordinates
        old_r0y=old_coord[1]

# Insert below the lines defining the new x and y positions based on the old ones + forces + mass + dtstep.
#
# Forces are contained in force[0] for the x force component and force[1] for the y force.
# The step size for the move is given by dtstep.
#
# ====>>>>>
        new_r0x = 2*r0x - old_r0x + force[0]/mass * dtstep**2
        new_r0y = 2*r0y - old_r0y + force[1]/mass * dtstep**2
# <<<<<====
        new_positions.append([new_r0x,new_r0y,coord[2]])
    return new_positions