<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_valid_object_name(sequence):
 """Check that the names of the objects are all different."""

    names = []
    for o in sequence:
        if o.__name__ in names:
            raise ValueError(
                'A tallyable PyMC object called %s already exists. This will cause problems for some database backends.' %
                o.__name__)
        else:
            names.append(o.__name__)