<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def call_MediaInfo(file_name, mediainfo_path=None):
 """Returns a dictionary of dictionaries with the output of MediaInfo -f file_name"""

    if mediainfo_path is None:
        mediainfo_path = find_MediaInfo()

    result = subprocess.check_output(
        [mediainfo_path, "-f", file_name], universal_newlines=True
    )
    D = collections.defaultdict(dict)
    for line in result.splitlines():
        line = line.split(':', 1)
        # Skip separators
        if line[0] == '':
            continue
        # Start a new section
        elif len(line) == 1:
            section = line[0].strip()
        # Record section key, value pairs
        else:
            k = line[0].strip()
            v = line[1].strip()
            if k not in D[section]:
                D[section][k] = v

    return D