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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 map_equal_contributions(contributors):
 """assign numeric values to each unique equal-contrib id"""

    equal_contribution_map = {}
    equal_contribution_keys = []
    for contributor in contributors:
        if contributor.get("references") and "equal-contrib" in contributor.get("references"):
            for key in contributor["references"]["equal-contrib"]:
                if key not in equal_contribution_keys:
                    equal_contribution_keys.append(key)
    # Do a basic sort
    equal_contribution_keys = sorted(equal_contribution_keys)
    # Assign keys based on sorted values
    for i, equal_contribution_key in enumerate(equal_contribution_keys):
        equal_contribution_map[equal_contribution_key] = i+1
    return equal_contribution_map