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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 describe_pdb(pdb_id):
 """Get description and metadata of a PDB entry Parameters pdb_id : string A 4 character string giving a pdb entry of interest Returns ------- out : string A text pdb description from PDB Examples -------- {'citation_authors': 'Malashkevich, V.N., Bhosle, R., Toro, R., Hillerich, B., Gizzi, A., Garforth, S., Kar, A., Chan, M.K., Lafluer, J., Patel, H., Matikainen, B., Chamala, S., Lim, S., Celikgil, A., Villegas, G., Evans, B., Love, J., Fiser, A., Khafizov, K., Seidel, R., Bonanno, J.B., Almo, S.C.', 'deposition_date': '2013-07-31', 'expMethod': 'X-RAY DIFFRACTION', 'keywords': 'TRANSFERASE', 'last_modification_date': '2013-08-14', 'nr_atoms': '0', 'nr_entities': '1', 'nr_residues': '390', 'release_date': '2013-08-14', 'resolution': '1.84', 'status': 'CURRENT', 'structureId': '4LZA', 'structure_authors': 'Malashkevich, V.N., Bhosle, R., Toro, R., Hillerich, B., Gizzi, A., Garforth, S., Kar, A., Chan, M.K., Lafluer, J., Patel, H., Matikainen, B., Chamala, S., Lim, S., Celikgil, A., Villegas, G., Evans, B., Love, J., Fiser, A., Khafizov, K., Seidel, R., Bonanno, J.B., Almo, S.C., New York Structural Genomics Research Consortium (NYSGRC)', 'title': 'Crystal structure of adenine phosphoribosyltransferase from Thermoanaerobacter pseudethanolicus ATCC 33223, NYSGRC Target 029700.'} """

    out = get_info(pdb_id, url_root = 'http://www.rcsb.org/pdb/rest/describePDB?structureId=')
    out = to_dict(out)
    out = remove_at_sign(out['PDBdescription']['PDB'])
    return out