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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def defines_to_dict(defines):
 """Convert a list of definition strings to a dictionary."""

    if defines is None:
        return None
    result = {}
    for define in defines:
        kv = define.split('=', 1)
        if len(kv) == 1:
            result[define.strip()] = 1
        else:
            result[kv[0].strip()] = kv[1].strip()
    return result