<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def submitted_projects(raw_df):
 """ Return all submitted projects. """

    df = raw_df.astype({'PRONAC': str, 'CgcCpf': str})
    submitted_projects = df.groupby('CgcCpf')[
        'PRONAC'
    ].agg(['unique', 'nunique'])

    submitted_projects.columns = ['pronac_list', 'num_pronacs']

    return submitted_projects