code: def _is_a_url(input_element):
      
      if type(input_element) is str:
          # Check if signal_handler is a url.
          # [Statements to be executed if signal_handler is a url]
          if any(mark in input_element for mark in ["http://", "https://", "www.", ".pt", ".com",
                                                    ".org", ".net"]):
              return True
          else:
              return False
      else:
          return False
docs: -----
      Brief
      -----
      Auxiliary function responsible for checking if the input is a string that contains an url.
  
      -----------
      Description
      -----------
      Some biosignalsnotebooks functions support a remote access to files. In this situation it is
      important to understand if the input is an url, which can be easily achieved by checking if some
      key-markers are present.
  
      The key-markers that will be searched are "http://", "https://", "www.", ".pt", ".com", ".org",
      ".net".
  
      ----------
      Parameters
      ----------
      input_element : unknown
          The data structure that will be checked.
  
      Returns
      -------
      out : bool
          If the input_element is a string and if it contains any key-marker, then True flag will be returned.