code: public Source resolve(Field field) {
          
          /**
           * As promised the registrar simply abstracts away the internal 
           * resolution implementations, throwing an error if all of them fail to
           * come up with a source for the field.
           */
          for (Resolver resolver : resolvers) {
              Source source = resolver.resolve(field);
              
              /**
               * Per the dependency resolver contract, a return value of null 
               * means no error occurred, but the resolver failed to resolve the
               * type anyway, so we can move on to the next resolver.
               */
              if (source != null) {
                  return source;
              }
          }
          
          /**
           * If no resolver succeeded in generating an instance source, we've got
           * a problem: we need to inject a field but we have no way to get an
           * instance of it!
           */
          throw new UnexpectedImplementationCountException(
              field.getType(), 
              noImplementations);
      }
docs: Resolves a field into a
  {@link com.github.msoliter.iroh.container.resolvers.sources.base.Source}.
  
  @param field The field to be resolved.
  @return A source of instances accepted by the field.